Try todo some validation of monitor size/padding in config sanity check.

include/helper.h

@@ -134,7 +134,7 @@ void remove_pid_file ( int fd );
  *
  * This functions exits the program with 1 when it finds an invalid configuration.
  */
-void config_sanity_check ( void );
+void config_sanity_check ( Display *display );
 
 /**
  * @param arg string to parse.

include/x11-helper.h

@@ -71,6 +71,7 @@ int window_send_message ( Display *display, Window target, Window subject,
 void monitor_dimensions ( Display *display, Screen *screen, int x, int y, workarea *mon );
 // Find the dimensions of the monitor specified by user.
 int monitor_get_dimension ( Display *display, Screen *screen, int monitor, workarea *mon );
+int monitor_get_smallest_size ( Display *display );
 
 /**
  * @param display The display.

source/helper.c

@@ -39,6 +39,7 @@
 #include <sys/stat.h>
 #include <ctype.h>
 #include "helper.h"
+#include "x11-helper.h"
 #include "rofi.h"
 
 static int  stored_argc   = 0;
@@ -536,7 +537,7 @@ void remove_pid_file ( int fd )
  *
  * This functions exits the program with 1 when it finds an invalid configuration.
  */
-void config_sanity_check (  )
+void config_sanity_check ( Display *display )
 {
     int     found_error = FALSE;
     GString *msg        = g_string_new (
@@ -554,7 +555,7 @@ void config_sanity_check (  )
         found_error         = TRUE;
     }
     if ( config.menu_width == 0 ) {
-        show_error_message ( "<b>config.menu_width</b>=0 is invalid. You cannot have a window with no width.", TRUE );
+        g_string_append_printf ( msg, "<b>config.menu_width</b>=0 is invalid. You cannot have a window with no width." );
         config.menu_columns = 50;
         found_error         = TRUE;
     }
@@ -572,9 +573,35 @@ void config_sanity_check (  )
             found_error        = 1;
         }
     }
+
+    // Check size
+    {
+        int ssize = monitor_get_smallest_size ( display );
+        if ( config.monitor >= 0 ) {
+            workarea mon;
+            if ( monitor_get_dimension ( display, DefaultScreenOfDisplay ( display ), config.monitor, &mon ) ) {
+                ssize = MIN ( mon.w, mon.h );
+            }
+            else{
+                g_string_append_printf ( msg, "\t<b>config.monitor</b>=%d Could not find monitor.\n", config.monitor );
+                ssize = 0;
+            }
+        }
+        // Have todo an estimate here.
+        if ( ( 2 * ( config.padding + config.menu_bw ) ) > ( 0.9 * ssize ) ) {
+            g_string_append_printf ( msg, "\t<b>config.padding+config.menu_bw</b>=%d is to big for the minimum size of the monitor: %d.\n",
+                                     ( config.padding + config.menu_bw ), ssize );
+
+            config.padding = 0;
+            config.menu_bw = 0;
+            found_error    = TRUE;
+        }
+    }
+
     if ( found_error ) {
         g_string_append ( msg, "Please update your configuration." );
         show_error_message ( msg->str, TRUE );
+        exit ( EXIT_FAILURE );
     }
 
     g_string_free ( msg, TRUE );

source/keyb.c

@@ -1,3 +1,5 @@
+#include <config.h>
+#include <string.h>
 #include "rofi.h"
 #include <X11/keysym.h>
 #include "x11-helper.h"

source/rofi.c

@@ -948,10 +948,17 @@ static void menu_resize ( MenuState *state )
         unsigned int last_length    = state->max_elements;
         int          element_height = state->line_height * config.element_height + config.line_margin;
         // Calculated new number of boxes.
-        unsigned int h = ( state->h - state->top_offset - config.padding );
+        int          h = ( state->h - state->top_offset - config.padding );
         if ( config.sidebar_mode == TRUE ) {
             h -= state->line_height + config.line_margin;
         }
+        if ( h < 0 ) {
+            fprintf ( stderr, "Current padding %d (on each side) does not fit within visible window %d.\n", config.padding, state->h );
+            h = ( state->h - state->top_offset - state->h / 3 );
+            if ( config.sidebar_mode == TRUE ) {
+                h -= state->line_height + config.line_margin;
+            }
+        }
         state->max_rows     = MAX ( 1, ( h / element_height ) );
         state->max_elements = state->max_rows * config.menu_columns;
         // Free boxes no longer needed.
@@ -1828,7 +1835,7 @@ static void reload_configuration ()
             load_configuration_dynamic ( temp_display );
 
             // Sanity check
-            config_sanity_check ( );
+            config_sanity_check ( temp_display );
             parse_keys_abe ();
             XCloseDisplay ( temp_display );
         }
@@ -2076,7 +2083,7 @@ int main ( int argc, char *argv[] )
     x11_setup ( display );
 
     // Sanity check
-    config_sanity_check ( );
+    config_sanity_check ( display );
     // Dump.
     // catch help request
     if ( find_arg (  "-h" ) >= 0 || find_arg (  "-help" ) >= 0 || find_arg (  "--help" ) >= 0 ) {

source/x11-helper.c

@@ -143,7 +143,26 @@ int window_get_cardinal_prop ( Display *display, Window w, Atom atom, unsigned l
     Atom type; int items;
     return window_get_prop ( display, w, atom, &type, &items, list, count * sizeof ( unsigned long ) ) && type == XA_CARDINAL ? items : 0;
 }
+int monitor_get_smallest_size ( Display *display )
+{
+    int size = MIN ( WidthOfScreen ( DefaultScreenOfDisplay ( display ) ),
+                     HeightOfScreen ( DefaultScreenOfDisplay ( display ) ) );
+    // locate the current monitor
+    if ( XineramaIsActive ( display ) ) {
+        int                monitors;
+        XineramaScreenInfo *info = XineramaQueryScreens ( display, &monitors );
 
+        if ( info ) {
+            for ( int i = 0; i < monitors; i++ ) {
+                size = MIN ( info[i].width, size );
+                size = MIN ( info[i].height, size );
+            }
+        }
+        XFree ( info );
+    }
+
+    return size;
+}
 int monitor_get_dimension ( Display *display, Screen *screen, int monitor, workarea *mon )
 {
     memset ( mon, 0, sizeof ( workarea ) );

test/helper-test.c

@@ -21,6 +21,13 @@ int show_error_message ( const char *msg, int markup )
     error_dialog ( msg, markup );
     return 0;
 }
+#include <x11-helper.h>
+int monitor_get_smallest_size ( Display *d )
+{
+}
+int monitor_get_dimension ( Display *d, Screen *screen, int monitor, workarea *mon )
+{
+}
 
 int main ( int argc, char ** argv )
 {