diff -u xsane-0.996.orig/src/xsane-preview.c xsane-0.996/src/xsane-preview.c
--- xsane-0.996.orig/src/xsane-preview.c
+++ xsane-0.996/src/xsane-preview.c
@@ -80,7 +80,6 @@
 #include "xsane-preview.h"
 #include "xsane-preferences.h"
 #include "xsane-gamma.h"
-#include <gdk/gdkkeysyms.h>
 
 
 #ifndef PATH_MAX
@@ -3022,9 +3021,9 @@
     preview_display_color_components(p, event->motion.x, event->motion.y);
 
     switch (((GdkEventMotion *)event)->state &
-            GDK_Num_Lock & GDK_Caps_Lock & GDK_Shift_Lock & GDK_Scroll_Lock) /* mask all Locks */
+            (GDK_BUTTON1_MASK | GDK_BUTTON2_MASK | GDK_BUTTON3_MASK)) /* only check for mouse buttons */
     {
-      case 256: /* left button */
+      case GDK_BUTTON1_MASK: /* left button */
 
         DBG(DBG_info2, "left button\n");
 
@@ -3291,8 +3290,8 @@
         }
        break;
 
-      case 512: /* middle button */
-      case 1024: /* right button */
+      case GDK_BUTTON2_MASK: /* middle button */
+      case GDK_BUTTON3_MASK: /* right button */
         DBG(DBG_info2, "middle or right button\n");
 
         if (p->selection_drag)