diff --git a/include/theme.h b/include/theme.h
index e96636d2..1eaf4718 100644
--- a/include/theme.h
+++ b/include/theme.h
@@ -2,27 +2,48 @@
 #define THEME_H
 #include <glib.h>
 #include <cairo.h>
-typedef enum {
-    PW_PX,
-    PW_EM,
 
+/**
+ * Distance unit type.
+ */
+typedef enum {
+    /** PixelWidth in pixels. */
+    PW_PX,
+    /** PixelWidth in EM. */
+    PW_EM,
 } PixelWidth;
 
+/**
+ * Structure representing a distance.
+ */
 typedef struct {
+    /** Distance */
     double     distance;
+    /** Unit type of the distance */
     PixelWidth type;
 } Distance;
 
+/**
+ * Type of property
+ */
 typedef enum {
+    /** Integer */
     P_INTEGER,
+    /** Double */
     P_DOUBLE,
+    /** String */
     P_STRING,
+    /** Boolean */
     P_BOOLEAN,
+    /** Color */
     P_COLOR,
-    // Used in padding.
+    /** Padding */
     P_PADDING,
 } PropertyType;
 
+/**
+ * Represent the color in theme.
+ */
 typedef struct
 {
     /** red channel */
@@ -35,6 +56,9 @@ typedef struct
     double alpha;
 } ThemeColor;
 
+/**
+ * Padding
+ */
 typedef struct
 {
     Distance top;
@@ -55,45 +79,189 @@ typedef struct {
         Padding    padding;
     } value;
 } Property;
-
-typedef struct _Widget {
+/**
+ * ThemeWidget.
+ */
+typedef struct ThemeWidget {
     int set;
     char *name;
 
     unsigned int num_widgets;
-    struct _Widget **widgets;
+    struct ThemeWidget **widgets;
 
     GHashTable *properties;
 
-    struct _Widget *parent;
-} Widget;
+    struct ThemeWidget *parent;
+} ThemeWidget;
 
 
-extern Widget *rofi_theme;
+/**
+ * Global pointer to the current active theme.
+ */
+extern ThemeWidget *rofi_theme;
 
-Widget *rofi_theme_find_or_create_class ( Widget *base, const char *class );
+/**
+ * @param base Handle to the current level in the theme.
+ * @param class Name of the new element.
+ *
+ * Create a new element in the theme structure.
+ *
+ * @returns handle to the new entry.
+ */
+ThemeWidget *rofi_theme_find_or_create_class ( ThemeWidget *base, const char *class );
 
+/**
+ * @param widget The widget handle.
+ *
+ * Print out the widget to the commandline.
+ */
+void rofi_theme_print ( ThemeWidget *widget );
 
-void rofi_theme_print ( Widget *widget );
-
+/**
+ * @param type The type of the property to create.
+ *
+ * Create a theme property of type.
+ *
+ * @returns a new property.
+ */
 Property *rofi_theme_property_create ( PropertyType type );
+
+/**
+ * @param p The property to free.
+ *
+ * Free the content of the property.
+ */
 void rofi_theme_property_free ( Property *p );
-void rofi_theme_free ( Widget * );
+
+/**
+ * @param wid
+ *
+ * Free the widget and alll children.
+ */
+void rofi_theme_free ( ThemeWidget * );
+
+/**
+ * @param file filename to parse. 
+ *
+ * Parse the input theme file.
+ */
 void rofi_theme_parse_file ( const char *file );
-void rofi_theme_widget_add_properties ( Widget *widget, GHashTable *table );
+
+/**
+ * @param widget The widget handle.
+ * @param table HashTable containing properties set.
+ *
+ * Merge properties with widgets current property.
+ */
+void rofi_theme_widget_add_properties ( ThemeWidget *widget, GHashTable *table );
 
 /**
  * Public API
  */
 
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the distance of the widget.
+ *
+ * @returns The distance value of this property for this widget. 
+ */
 Distance rofi_theme_get_distance ( const char *wclass, const char  *name, const char *state, const char *property, int def );
+
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the integer of the widget.
+ *
+ * @returns The integer value of this property for this widget. 
+ */
 int rofi_theme_get_integer   ( const char *wclass,  const char *name, const char *state,  const char *property, int def );
+
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the boolean of the widget.
+ *
+ * @returns The boolean value of this property for this widget. 
+ */
 int rofi_theme_get_boolean   ( const char *wclass,  const char *name, const char *state,  const char *property, int def );
+
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the string of the widget.
+ *
+ * @returns The string value of this property for this widget. 
+ */
 char *rofi_theme_get_string  ( const char *wclass,  const char *name, const char *state,  const char *property, char *def );
+
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the padding of the widget.
+ *
+ * @returns The double value of this property for this widget. 
+ */
 double rofi_theme_get_double ( const char *wclass,  const char *name, const char *state,  const char *property, double def );
+
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the color of the widget.
+ *
+ * @returns The color value of this property for this widget. 
+ */
 void rofi_theme_get_color ( const char *wclass, const char  *name, const char *state, const char *property, cairo_t *d);
+
+/**
+ * @param wclass   The widget class
+ * @param name     The name class
+ * @param state    The widget current state
+ * @param property The property to query.
+ * @param def      The default value.
+ *
+ * Obtain the padding of the widget.
+ *
+ * @returns The padding of this property for this widget. 
+ */
 Padding rofi_theme_get_padding ( const char *wclass, const char  *name, const char *state, const char *property, Padding pad );
 
+/**
+ * @param d The distance handle.
+ *
+ * Convert Distance into pixels.
+ * @returns the number of pixels this distance represents.
+ */
 int distance_get_pixel ( Distance d );
+
+#ifdef THEME_CONVERTER
+/**
+ * Function to convert old theme into new theme format.
+ */
 void rofi_theme_convert_old_theme ( void );
 #endif
+#endif
diff --git a/include/view-internal.h b/include/view-internal.h
index f2f000bb..96dffdb7 100644
--- a/include/view-internal.h
+++ b/include/view-internal.h
@@ -24,7 +24,7 @@ struct RofiViewState
 
     /** Flag indicating if view needs to be refiltered. */
     int              refilter;
-
+    /** Widget representing the main window. */
     window           *main_window;
     /** Main #box widget holding different elements. */
     box              *main_box;
diff --git a/include/widgets/scrollbar.h b/include/widgets/scrollbar.h
index 0abfa521..4efbaaa5 100644
--- a/include/widgets/scrollbar.h
+++ b/include/widgets/scrollbar.h
@@ -63,6 +63,12 @@ void scrollbar_set_max_value ( scrollbar *sb, unsigned int max );
  */
 unsigned int scrollbar_clicked ( const scrollbar *sb, int y );
 
+/**
+ * @param sb scrollbar object
+ * @param width width of the scrollbar
+ *
+ * Set the width of the scrollbar handle.
+ */
 void scrollbar_set_width ( scrollbar *sb, int width );
 /*@}*/
 #endif // ROFI_SCROLLBAR_H
diff --git a/include/widgets/textbox.h b/include/widgets/textbox.h
index 14484a25..1b6a4152 100644
--- a/include/widgets/textbox.h
+++ b/include/widgets/textbox.h
@@ -196,6 +196,12 @@ int textbox_get_font_width ( const textbox *tb );
  * @returns the width of a character in pixels.
  */
 double textbox_get_estimated_char_width ( void );
+
+/**
+ * Estimate the height of a character.
+ *
+ * @returns the height of a character in pixels.
+ */
 double textbox_get_estimated_char_height ( void  );
 
 /**
@@ -255,6 +261,5 @@ PangoAttrList *textbox_get_pango_attributes ( textbox *tb );
  * @returns the visible text.
  */
 const char *textbox_get_visible_text ( const textbox *tb );
-int distance_get_pixel ( Distance d );
 /*@}*/
 #endif //ROFI_TEXTBOX_H
diff --git a/include/widgets/widget-internal.h b/include/widgets/widget-internal.h
index 0eb1ef54..5151c8b1 100644
--- a/include/widgets/widget-internal.h
+++ b/include/widgets/widget-internal.h
@@ -57,15 +57,90 @@ struct _widget
     const char *state;
 };
 
+/**
+ * @param widget The widget to initialize.
+ * @param name The name of the widget.
+ * @param class The class of the widget.
+ *
+ * Initializes the @widget structure.
+ *
+ */
 void widget_init ( widget *widget , const char *name, const char *class_name );
+
+/**
+ * @param widget The widget handle.
+ * @param state  The state of the widget.
+ *
+ * Set the state of the widget.
+ */
 void widget_set_state ( widget *widget, const char *state );
 
+/**
+ * @param wid The widget handle.
+ *
+ * Get the left padding of the widget.
+ *
+ * @returns the left padding in pixels.
+ */
 int widget_padding_get_left ( const widget *wid );
+
+/**
+ * @param wid The widget handle.
+ *
+ * Get the right padding of the widget.
+ *
+ * @returns the right padding in pixels.
+ */
 int widget_padding_get_right ( const widget *wid );
+
+/**
+ * @param wid The widget handle.
+ *
+ * Get the top padding of the widget.
+ *
+ * @returns the top padding in pixels.
+ */
 int widget_padding_get_top ( const widget *wid );
+
+/**
+ * @param wid The widget handle.
+ *
+ * Get the bottom padding of the widget.
+ *
+ * @returns the bottom padding in pixels.
+ */
 int widget_padding_get_bottom ( const widget *wid );
+
+/**
+ * @param wid The widget handle.
+ *
+ * Get width of the content of the widget 
+ *
+ * @returns the widget width, excluding padding. 
+ */
 int widget_padding_get_remaining_width ( const widget *wid );
+/**
+ * @param wid The widget handle.
+ *
+ * Get height of the content of the widget 
+ *
+ * @returns the widget height, excluding padding. 
+ */
 int widget_padding_get_remaining_height ( const widget *wid );
+/**
+ * @param wid The widget handle.
+ *
+ * Get the combined top and bottom padding.
+ *
+ * @returns the top and bottom padding of the widget in pixels.
+ */
 int widget_padding_get_padding_height ( const widget *wid );
+/**
+ * @param wid The widget handle.
+ *
+ * Get the combined left and right padding.
+ *
+ * @returns the left and right padding of the widget in pixels.
+ */
 int widget_padding_get_padding_width ( const widget *wid );
 #endif // WIDGET_INTERNAL_H
diff --git a/include/widgets/widget.h b/include/widgets/widget.h
index 03e85387..9dda0457 100644
--- a/include/widgets/widget.h
+++ b/include/widgets/widget.h
@@ -175,7 +175,22 @@ void widget_set_clicked_handler ( widget *wid, widget_clicked_cb cb, void *udata
 gboolean widget_motion_notify ( widget *wid, xcb_motion_notify_event_t *xme );
 
 
+/**
+ * @param wid The widget handle
+ * @param name The name of the widget.
+ *
+ * Set name on widget.
+ */
 void widget_set_name ( widget *wid, const char *name );
+
+/**
+ * @param wid The widget handle
+ *
+ * Get the desired height of this widget recursively.
+ *
+ * @returns the desired height of the widget in pixels.
+ */
 int widget_get_desired_height ( widget *wid );
+
 /*@}*/
 #endif // ROFI_WIDGET_H
diff --git a/include/widgets/window.h b/include/widgets/window.h
index 6d8a90a1..3c320d10 100644
--- a/include/widgets/window.h
+++ b/include/widgets/window.h
@@ -32,6 +32,13 @@ window * window_create ( const char *name );
  */
 void window_add ( window *window, widget *child );
 
+/**
+ * @param window Handle to the window widget.
+ * 
+ * Get the border width of the widget.
+ *
+ * @returns the border width (times 2) of the widget.
+ */
 int window_get_border_width ( const window *window );
 /*@}*/
 #endif // ROFI_WINDOW_H
diff --git a/lexer/theme-parser.y b/lexer/theme-parser.y
index e2f7795f..9730de7a 100644
--- a/lexer/theme-parser.y
+++ b/lexer/theme-parser.y
@@ -16,7 +16,7 @@
 
 #include "theme.h"
 #include "lexer/theme-parser.h"
-Widget *rofi_theme = NULL;
+ThemeWidget *rofi_theme = NULL;
 void yyerror(YYLTYPE *yylloc, const char* s);
 int yylex (YYSTYPE *, YYLTYPE *);
 %}
@@ -27,7 +27,7 @@ int yylex (YYSTYPE *, YYLTYPE *);
     char          *sval;
     int           bval;
     ThemeColor    colorval;
-    Widget        *theme;
+    ThemeWidget        *theme;
     GList         *name_path;
     Property      *property;
     GHashTable    *property_list;
@@ -79,7 +79,7 @@ start:
 entries:
   %empty {
         // There is always a base widget.
-        $$ =  rofi_theme = (Widget*)g_malloc0 (sizeof(Widget));
+        $$ =  rofi_theme = (ThemeWidget*)g_malloc0 (sizeof(ThemeWidget));
         rofi_theme->name = g_strdup ( "Root" );
   }
 |  entries
@@ -94,7 +94,7 @@ entry:
 CLASS_PREFIX class_name state_path BOPEN optional_properties BCLOSE
 {
         gchar *classn = g_strconcat ( "@", $2, NULL);
-        Widget *widget = rofi_theme_find_or_create_class ( rofi_theme , classn );
+        ThemeWidget *widget = rofi_theme_find_or_create_class ( rofi_theme , classn );
         g_free(classn);
         widget->set = TRUE;
         for ( GList *iter = g_list_first ( $3 ); iter ; iter = g_list_next ( iter ) ) {
@@ -107,7 +107,7 @@ CLASS_PREFIX class_name state_path BOPEN optional_properties BCLOSE
 }
 | NAME_PREFIX name_path state_path BOPEN optional_properties BCLOSE
 {
-        Widget *widget = rofi_theme;
+        ThemeWidget *widget = rofi_theme;
         for ( GList *iter = g_list_first ( $2 ); iter ; iter = g_list_next ( iter ) ) {
             widget = rofi_theme_find_or_create_class ( widget, iter->data );
         }
diff --git a/source/theme.c b/source/theme.c
index 13c1d1cd..8bba8206 100644
--- a/source/theme.c
+++ b/source/theme.c
@@ -10,7 +10,7 @@
 
 void yyerror ( YYLTYPE *ylloc, const char *);
 
-Widget *rofi_theme_find_or_create_class ( Widget *base, const char *class )
+ThemeWidget *rofi_theme_find_or_create_class ( ThemeWidget *base, const char *class )
 {
     for ( unsigned int i = 0; i < base->num_widgets;i++){
         if ( g_strcmp0(base->widgets[i]->name, class) == 0 ){
@@ -18,9 +18,9 @@ Widget *rofi_theme_find_or_create_class ( Widget *base, const char *class )
         }
     }
 
-    base->widgets = g_realloc ( base->widgets, sizeof(Widget*)*(base->num_widgets+1));
-    base->widgets[base->num_widgets] = g_malloc0(sizeof(Widget));
-    Widget *retv = base->widgets[base->num_widgets];
+    base->widgets = g_realloc ( base->widgets, sizeof(ThemeWidget*)*(base->num_widgets+1));
+    base->widgets[base->num_widgets] = g_malloc0(sizeof(ThemeWidget));
+    ThemeWidget *retv = base->widgets[base->num_widgets];
     retv->parent = base;
     retv->name = g_strdup(class);
     base->num_widgets++;
@@ -47,7 +47,7 @@ void rofi_theme_property_free ( Property *p )
     g_free(p);
 }
 
-void rofi_theme_free ( Widget *widget )
+void rofi_theme_free ( ThemeWidget *widget )
 {
     if ( widget == NULL ){
         return;
@@ -116,14 +116,14 @@ static void rofi_theme_print_property_index ( int depth, Property *p )
     putchar ( '\n' );
 }
 
-static void rofi_theme_print_index ( Widget *widget )
+static void rofi_theme_print_index ( ThemeWidget *widget )
 {
     GHashTableIter iter;
     gpointer key, value;
     if ( widget->properties ){
         int index = 0;
         GList *list = NULL;
-        Widget *w = widget;
+        ThemeWidget *w = widget;
         while ( w){
             if ( g_strcmp0(w->name,"Root") == 0 ) {
                 break;
@@ -164,16 +164,32 @@ static void rofi_theme_print_index ( Widget *widget )
         rofi_theme_print_index ( widget->widgets[i] );
     }
 }
-void rofi_theme_print ( Widget *widget )
+void rofi_theme_print ( ThemeWidget *widget )
 {
     rofi_theme_print_index ( widget );
 }
 
+/**
+ * Main lex parser.
+ */
 int yyparse();
-void yylex_destroy( void );
-extern FILE* yyin;
-extern Widget *rofi_theme;
 
+/**
+ * Destroy the internal of lex parser.
+ */
+void yylex_destroy( void );
+
+/**
+ * Global handle input file to flex parser.
+ */
+extern FILE* yyin;
+
+/**
+ * @param yylloc The file location.
+ * @param s      Error message string.
+ *
+ * Error handler for the lex parser.
+ */
 void yyerror(YYLTYPE *yylloc, const char* s) {
 	fprintf(stderr, "Parse error: %s\n", s);
     fprintf(stderr, "From line %d column %d to line %d column %d\n", yylloc->first_line, yylloc->first_column, yylloc->last_line, yylloc->last_column);
@@ -186,7 +202,7 @@ static gboolean rofi_theme_steal_property_int ( gpointer key, gpointer value, gp
     g_hash_table_replace ( table, key, value);
     return TRUE;
 }
-void rofi_theme_widget_add_properties ( Widget *widget, GHashTable *table )
+void rofi_theme_widget_add_properties ( ThemeWidget *widget, GHashTable *table )
 {
     if ( table == NULL ) {
         return;
@@ -204,7 +220,7 @@ void rofi_theme_widget_add_properties ( Widget *widget, GHashTable *table )
  * Public API
  */
 
-static Widget *rofi_theme_find_single ( Widget *widget, const char *name)
+static ThemeWidget *rofi_theme_find_single ( ThemeWidget *widget, const char *name)
 {
     for ( unsigned int j = 0; j < widget->num_widgets;j++){
         if ( g_strcmp0(widget->widgets[j]->name, name ) == 0 ){
@@ -214,7 +230,7 @@ static Widget *rofi_theme_find_single ( Widget *widget, const char *name)
     return widget;
 }
 
-static Widget *rofi_theme_find ( Widget *widget , const char *name, const gboolean exact )
+static ThemeWidget *rofi_theme_find ( ThemeWidget *widget , const char *name, const gboolean exact )
 {
     if ( widget  == NULL  || name == NULL ) {
         return widget;
@@ -223,7 +239,7 @@ static Widget *rofi_theme_find ( Widget *widget , const char *name, const gboole
     int found = TRUE;
     for ( unsigned int i = 0; found && names && names[i]; i++ ){
         found = FALSE;
-        Widget *f = rofi_theme_find_single ( widget, names[i]);
+        ThemeWidget *f = rofi_theme_find_single ( widget, names[i]);
         if ( f != widget ){
             widget = f;
             found = TRUE;
@@ -237,7 +253,7 @@ static Widget *rofi_theme_find ( Widget *widget , const char *name, const gboole
     }
 }
 
-static Property *rofi_theme_find_property ( Widget *widget, PropertyType type, const char *property )
+static Property *rofi_theme_find_property ( ThemeWidget *widget, PropertyType type, const char *property )
 {
     while ( widget ) {
         if ( widget->properties && g_hash_table_contains ( widget->properties, property) ) {
@@ -250,10 +266,10 @@ static Property *rofi_theme_find_property ( Widget *widget, PropertyType type, c
     }
     return NULL;
 }
-static Widget *rofi_theme_find_widget ( const char *wclass, const char *name, const char *state )
+static ThemeWidget *rofi_theme_find_widget ( const char *wclass, const char *name, const char *state )
 {
     // First find exact match based on name.
-    Widget *widget = rofi_theme_find ( rofi_theme, name, TRUE );
+    ThemeWidget *widget = rofi_theme_find ( rofi_theme, name, TRUE );
     widget = rofi_theme_find ( widget, state, TRUE );
 
     if ( widget == NULL ){
@@ -274,7 +290,7 @@ static Widget *rofi_theme_find_widget ( const char *wclass, const char *name, co
 
 int rofi_theme_get_integer ( const char *wclass, const char  *name, const char *state, const char *property, int def )
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_INTEGER, property );
     if ( p ){
         return p->value.i;
@@ -283,7 +299,7 @@ int rofi_theme_get_integer ( const char *wclass, const char  *name, const char *
 }
 Distance rofi_theme_get_distance ( const char *wclass, const char  *name, const char *state, const char *property, int def )
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_PADDING, property );
     if ( p ){
         return p->value.padding.left;
@@ -298,7 +314,7 @@ Distance rofi_theme_get_distance ( const char *wclass, const char  *name, const
 
 int rofi_theme_get_boolean ( const char *wclass, const char  *name, const char *state, const char *property, int def )
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_BOOLEAN, property );
     if ( p ){
         return p->value.b;
@@ -308,7 +324,7 @@ int rofi_theme_get_boolean ( const char *wclass, const char  *name, const char *
 
 char *rofi_theme_get_string ( const char *wclass, const char  *name, const char *state, const char *property, char *def )
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_STRING, property );
     if ( p ){
         return p->value.s;
@@ -317,7 +333,7 @@ char *rofi_theme_get_string ( const char *wclass, const char  *name, const char
 }
 double rofi_theme_get_double ( const char *wclass, const char  *name, const char *state, const char *property, double def )
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_DOUBLE, property );
     if ( p ){
         return p->value.b;
@@ -326,7 +342,7 @@ double rofi_theme_get_double ( const char *wclass, const char  *name, const char
 }
 void rofi_theme_get_color ( const char *wclass, const char  *name, const char *state, const char *property, cairo_t *d)
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_COLOR, property );
     if ( p ){
         cairo_set_source_rgba ( d,
@@ -340,7 +356,7 @@ void rofi_theme_get_color ( const char *wclass, const char  *name, const char *s
 }
 Padding rofi_theme_get_padding ( const char *wclass, const char  *name, const char *state, const char *property, Padding pad )
 {
-    Widget *widget = rofi_theme_find_widget ( wclass, name, state );
+    ThemeWidget *widget = rofi_theme_find_widget ( wclass, name, state );
     Property *p = rofi_theme_find_property ( widget, P_PADDING, property );
     if ( p ){
         pad = p->value.padding;
@@ -385,12 +401,12 @@ void rofi_theme_convert_old_theme ( void )
     if ( rofi_theme != NULL ){
         return;
     }
-    rofi_theme = (Widget*)g_malloc0 ( sizeof ( Widget ) );
+    rofi_theme = (ThemeWidget*)g_malloc0 ( sizeof ( ThemeWidget ) );
     rofi_theme->name = g_strdup ( "Root" );
     rofi_theme->properties = rofi_theme_convert_create_property_ht ( );
     {
         // Spacing
-        Widget *box_widget = rofi_theme_find_or_create_class ( rofi_theme , "@box" );
+        ThemeWidget *box_widget = rofi_theme_find_or_create_class ( rofi_theme , "@box" );
         box_widget->properties = rofi_theme_convert_create_property_ht ( );
         Property *p = rofi_theme_property_create ( P_INTEGER );
         p->name = g_strdup("spacing");
@@ -399,7 +415,7 @@ void rofi_theme_convert_old_theme ( void )
     }
     {
         // Spacing
-        Widget *listview_widget = rofi_theme_find_or_create_class ( rofi_theme , "@listview" );
+        ThemeWidget *listview_widget = rofi_theme_find_or_create_class ( rofi_theme , "@listview" );
         listview_widget->properties = rofi_theme_convert_create_property_ht ( );
         Property *p = rofi_theme_property_create ( P_INTEGER );
         p->name = g_strdup("spacing");
@@ -408,7 +424,7 @@ void rofi_theme_convert_old_theme ( void )
     }
     {
         // Border width.
-        Widget *window_widget = rofi_theme_find_or_create_class ( rofi_theme , "@window" );
+        ThemeWidget *window_widget = rofi_theme_find_or_create_class ( rofi_theme , "@window" );
         window_widget->properties = rofi_theme_convert_create_property_ht ( );
         Property *p = rofi_theme_property_create ( P_INTEGER );
         p->name = g_strdup("border-width");
@@ -432,7 +448,7 @@ void rofi_theme_convert_old_theme ( void )
                     g_hash_table_replace ( rofi_theme->properties, p->name, p );
 
                    if ( vals[2] != NULL ) {
-                       Widget *widget = rofi_theme_find_or_create_class ( rofi_theme , "@separator" );
+                       ThemeWidget *widget = rofi_theme_find_or_create_class ( rofi_theme , "@separator" );
                        widget->properties = rofi_theme_convert_create_property_ht ();
                        p = rofi_theme_convert_get_color ( vals[1], "foreground" );
                        g_hash_table_replace ( widget->properties, p->name, p );
@@ -444,30 +460,30 @@ void rofi_theme_convert_old_theme ( void )
         g_strfreev ( vals );
         {
             Property *p = NULL;
-            Widget *widget = rofi_theme_find_or_create_class ( rofi_theme , "@textbox" );
+            ThemeWidget *widget = rofi_theme_find_or_create_class ( rofi_theme , "@textbox" );
 
-            Widget *wnormal = rofi_theme_find_or_create_class ( widget, "normal" );
-            Widget *wselected = rofi_theme_find_or_create_class ( widget, "selected" );
-            Widget *walternate = rofi_theme_find_or_create_class ( widget, "alternate" );
+            ThemeWidget *wnormal = rofi_theme_find_or_create_class ( widget, "normal" );
+            ThemeWidget *wselected = rofi_theme_find_or_create_class ( widget, "selected" );
+            ThemeWidget *walternate = rofi_theme_find_or_create_class ( widget, "alternate" );
 
 
             gchar **vals = g_strsplit ( config.color_normal, ",", 5 );
             if ( g_strv_length (vals) == 5 ) {
-                Widget *wnn = rofi_theme_find_or_create_class ( wnormal, "normal" );
+                ThemeWidget *wnn = rofi_theme_find_or_create_class ( wnormal, "normal" );
                 wnn->properties = rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[0], "background" );
                 g_hash_table_replace ( wnn->properties, p->name, p );
                 p = rofi_theme_convert_get_color ( vals[1], "foreground" );
                 g_hash_table_replace ( wnn->properties, p->name, p );
 
-                Widget *wsl = rofi_theme_find_or_create_class ( wselected, "normal" );
+                ThemeWidget *wsl = rofi_theme_find_or_create_class ( wselected, "normal" );
                 wsl->properties = rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[3], "background" );
                 g_hash_table_replace ( wsl->properties, p->name, p );
                 p = rofi_theme_convert_get_color ( vals[4], "foreground" );
                 g_hash_table_replace ( wsl->properties, p->name, p );
 
-                Widget *wal = rofi_theme_find_or_create_class ( walternate, "normal" );
+                ThemeWidget *wal = rofi_theme_find_or_create_class ( walternate, "normal" );
                 wal->properties = rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[2], "background" );
                 g_hash_table_replace ( wal->properties, p->name, p );
@@ -478,21 +494,21 @@ void rofi_theme_convert_old_theme ( void )
 
             vals = g_strsplit ( config.color_urgent, ",", 5 );
             if ( g_strv_length (vals) == 5 ) {
-                Widget *wnn = rofi_theme_find_or_create_class ( wnormal, "urgent" );
+                ThemeWidget *wnn = rofi_theme_find_or_create_class ( wnormal, "urgent" );
                 wnn->properties =  rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[0], "background" );
                 g_hash_table_replace ( wnn->properties, p->name, p );
                 p = rofi_theme_convert_get_color ( vals[1], "foreground" );
                 g_hash_table_replace ( wnn->properties, p->name, p );
 
-                Widget *wsl = rofi_theme_find_or_create_class ( wselected, "urgent" );
+                ThemeWidget *wsl = rofi_theme_find_or_create_class ( wselected, "urgent" );
                 wsl->properties =  rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[3], "background" );
                 g_hash_table_replace ( wsl->properties, p->name, p );
                 p = rofi_theme_convert_get_color ( vals[4], "foreground" );
                 g_hash_table_replace ( wsl->properties, p->name, p );
 
-                Widget *wal = rofi_theme_find_or_create_class ( walternate, "urgent" );
+                ThemeWidget *wal = rofi_theme_find_or_create_class ( walternate, "urgent" );
                 wal->properties =  rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[2], "background" );
                 g_hash_table_replace ( wal->properties, p->name, p );
@@ -503,21 +519,21 @@ void rofi_theme_convert_old_theme ( void )
 
             vals = g_strsplit ( config.color_active, ",", 5 );
             if ( g_strv_length (vals) == 5 ) {
-                Widget *wnn = rofi_theme_find_or_create_class ( wnormal, "active" );
+                ThemeWidget *wnn = rofi_theme_find_or_create_class ( wnormal, "active" );
                 wnn->properties =  rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[0], "background" );
                 g_hash_table_replace ( wnn->properties, p->name, p );
                 p = rofi_theme_convert_get_color ( vals[1], "foreground" );
                 g_hash_table_replace ( wnn->properties, p->name, p );
 
-                Widget *wsl = rofi_theme_find_or_create_class ( wselected, "active" );
+                ThemeWidget *wsl = rofi_theme_find_or_create_class ( wselected, "active" );
                 wsl->properties =  rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[3], "background" );
                 g_hash_table_replace ( wsl->properties, p->name, p );
                 p = rofi_theme_convert_get_color ( vals[4], "foreground" );
                 g_hash_table_replace ( wsl->properties, p->name, p );
 
-                Widget *wal = rofi_theme_find_or_create_class ( walternate, "active" );
+                ThemeWidget *wal = rofi_theme_find_or_create_class ( walternate, "active" );
                 wal->properties =  rofi_theme_convert_create_property_ht ();
                 p = rofi_theme_convert_get_color ( vals[2], "background" );
                 g_hash_table_replace ( wal->properties, p->name, p );
diff --git a/source/widgets/box.c b/source/widgets/box.c
index 8a33984f..d113c2e0 100644
--- a/source/widgets/box.c
+++ b/source/widgets/box.c
@@ -32,8 +32,11 @@
 #include "theme.h"
 
 #define LOG_DOMAIN    "Widgets.Box"
+
+/** Class name of box widget */
 const char *BOX_CLASS_NAME = "@box";
 
+/** Default spacing used in the box*/
 #define DEFAULT_SPACING  2
 
 /**
diff --git a/source/widgets/textbox.c b/source/widgets/textbox.c
index 69b73473..e29ec051 100644
--- a/source/widgets/textbox.c
+++ b/source/widgets/textbox.c
@@ -127,9 +127,15 @@ textbox* textbox_create ( const char *name, TextboxFlags flags, TextBoxFontType
     return tb;
 }
 
+/**
+ * State names used for theming.
+ */
 const char const *const theme_prop_names[][3] = {
+    /** Normal row */
     {"normal.normal", "selected.normal", "alternate.normal"},
+    /** Urgent row */
     {"normal.urgent", "selected.urgent", "alternate.urgent"},
+    /** Active row */
     {"normal.active", "selected.active", "alternate.active"},
 };
 
@@ -758,6 +764,7 @@ int textbox_get_font_width ( const textbox *tb )
     return width;
 }
 
+/** Caching for the expected character height. */
 static double char_height = -1;
 double textbox_get_estimated_char_height ( void )
 {
@@ -768,6 +775,7 @@ double textbox_get_estimated_char_height ( void )
     return char_height;
 }
 
+/** Caching for the expected character width. */
 static double char_width = -1;
 double textbox_get_estimated_char_width ( void )
 {
diff --git a/source/widgets/widget.c b/source/widgets/widget.c
index 3e1f6f31..3c8471f4 100644
--- a/source/widgets/widget.c
+++ b/source/widgets/widget.c
@@ -213,8 +213,6 @@ void widget_set_name ( widget *wid, const char *name )
     wid->name = g_strdup ( name );
 }
 
-// External
-double textbox_get_estimated_char_height ( void );
 int widget_padding_get_left ( const widget *wid )
 {
     return distance_get_pixel ( wid->pad.left );
diff --git a/source/widgets/window.c b/source/widgets/window.c
index 657999c7..7d53d1b8 100644
--- a/source/widgets/window.c
+++ b/source/widgets/window.c
@@ -33,7 +33,9 @@
 
 #define LOG_DOMAIN    "Widgets.Window"
 
+/** The default border width of the window */
 #define DEFAULT_BORDER_WIDTH 2
+/** The class name of the window */
 const char *WINDOW_CLASS_NAME = "@window";
 
 /**