diff --git a/include/rofi.h b/include/rofi.h
index 432c94f2..27b29298 100644
--- a/include/rofi.h
+++ b/include/rofi.h
@@ -142,6 +142,4 @@ int token_match ( char **tokens, const char *input,
                   __attribute__( ( unused ) ) int index,
                   __attribute__( ( unused ) ) void *data );
 
-void config_sanity_check ( void );
-void config_print ( void );
 #endif
diff --git a/source/rofi.c b/source/rofi.c
index e434a0d6..362da0fa 100644
--- a/source/rofi.c
+++ b/source/rofi.c
@@ -67,12 +67,8 @@
 
 #include "xrmoptions.h"
 
-
 #define LINE_MARGIN            4
 
-#define OPAQUE                 0xffffffff
-#define OPACITY                "_NET_WM_WINDOW_OPACITY"
-
 #ifdef HAVE_I3_IPC_H
 #define I3_SOCKET_PATH_PROP    "I3_SOCKET_PATH"
 // This setting is no longer user configurable, but partial to this file:
@@ -256,7 +252,8 @@ static int ( *xerror )( Display *, XErrorEvent * );
     X ( _NET_WM_STATE_SKIP_TASKBAR ), \
     X ( _NET_WM_STATE_SKIP_PAGER ),   \
     X ( _NET_WM_STATE_ABOVE ),        \
-    X ( _NET_WM_DESKTOP )
+    X ( _NET_WM_DESKTOP ),            \
+    X ( _NET_WM_WINDOW_OPACITY )
 
 enum { EWMH_ATOMS ( ATOM_ENUM ), NETATOMS };
 const char *netatom_names[] = { EWMH_ATOMS ( ATOM_CHAR ) };
@@ -957,8 +954,8 @@ MenuReturn menu ( char **lines, char **input, char *prompt, Time *time, int *shi
         XStoreName ( display, box, "rofi" );
 
         // Hack to set window opacity.
-        unsigned int opacity_set = ( unsigned int ) ( ( config.window_opacity / 100.0 ) * OPAQUE );
-        XChangeProperty ( display, box, XInternAtom ( display, OPACITY, False ),
+        unsigned int opacity_set = ( unsigned int ) ( ( config.window_opacity / 100.0 ) * UINT32_MAX);
+        XChangeProperty ( display, box, netatoms[_NET_WM_WINDOW_OPACITY],
                           XA_CARDINAL, 32, PropModeReplace,
                           ( unsigned char * ) &opacity_set, 1L );
     }
@@ -1886,7 +1883,7 @@ static void cleanup ()
  *
  * This functions exits the program with 1 when it finds an invalid configuration.
  */
-void config_sanity_check ( void )
+static void config_sanity_check ( void )
 {
     if ( config.menu_lines == 0 ) {
         fprintf ( stderr, "config.menu_lines is invalid. You need at least one visible line.\n" );