Bug 732160 - menu activation with alt-somekey makes tools stay...

...in "alt-pressed" mode

Menu activation doesn't cause a focus-out becaus menu keyboard
grabbing is implemented with a simple gtk_grab_add() (the menu popup
never gets the focus). Therefore, the canvas never gets a focus-out
event and the pressed modifiers are stuck.

Fixed by connecting to "grab-notify" on the canvas, and artificially
releasing all modifiers when the canvas is shadowed by a grab.

app/display/gimpdisplayshell-tool-events.c

@@ -649,7 +649,7 @@ gimp_display_shell_canvas_tool_events (GtkWidget        *canvas,
 
         active_tool = tool_manager_get_active (gimp);
 
-        state &= ~gimp_display_shell_key_to_state (bevent->button);
+        state &= ~gimp_display_shell_button_to_state (bevent->button);
 
         if (bevent->button == 1)
           {
@@ -1233,6 +1233,36 @@ gimp_display_shell_canvas_tool_events (GtkWidget        *canvas,
   return return_val;
 }
 
+void
+gimp_display_shell_canvas_grab_notify (GtkWidget        *canvas,
+                                       gboolean          was_grabbed,
+                                       GimpDisplayShell *shell)
+{
+  GimpDisplay *display;
+  GimpImage   *image;
+  Gimp        *gimp;
+
+  /*  are we in destruction?  */
+  if (! shell->display || ! gimp_display_get_shell (shell->display))
+    return;
+
+  display = shell->display;
+  gimp    = gimp_display_get_gimp (display);
+  image   = gimp_display_get_image (display);
+
+  if (! image)
+    return;
+
+  GIMP_LOG (TOOL_EVENTS, "grab_notify (display %p): was_grabbed = %s",
+            display, was_grabbed ? "TRUE" : "FALSE");
+
+  if (! was_grabbed)
+    {
+      if (! gimp_image_is_empty (image))
+        tool_manager_modifier_state_active (gimp, 0, display);
+    }
+}
+
 void
 gimp_display_shell_buffer_stroke (GimpMotionBuffer *buffer,
                                   const GimpCoords *coords,
@@ -1359,17 +1389,21 @@ gimp_display_shell_key_to_state (gint key)
     case GDK_KEY_Alt_L:
     case GDK_KEY_Alt_R:
       return GDK_MOD1_MASK;
+
     case GDK_KEY_Shift_L:
     case GDK_KEY_Shift_R:
       return GDK_SHIFT_MASK;
+
     case GDK_KEY_Control_L:
     case GDK_KEY_Control_R:
       return GDK_CONTROL_MASK;
+
 #ifdef GDK_WINDOWING_QUARTZ
     case GDK_KEY_Meta_L:
     case GDK_KEY_Meta_R:
       return GDK_MOD2_MASK;
 #endif
+
     default:
       return 0;
     }

app/display/gimpdisplayshell-tool-events.h

@@ -26,6 +26,10 @@ gboolean   gimp_display_shell_events                  (GtkWidget        *widget,
 gboolean   gimp_display_shell_canvas_tool_events      (GtkWidget        *widget,
                                                        GdkEvent         *event,
                                                        GimpDisplayShell *shell);
+void       gimp_display_shell_canvas_grab_notify      (GtkWidget        *widget,
+                                                       gboolean          was_grabbed,
+                                                       GimpDisplayShell *shell);
+
 void       gimp_display_shell_buffer_stroke           (GimpMotionBuffer *buffer,
                                                        const GimpCoords *coords,
                                                        guint32           time,

app/display/gimpdisplayshell.c

@@ -584,6 +584,10 @@ gimp_display_shell_constructed (GObject *object)
   gimp_devices_add_widget (shell->display->gimp, shell->hrule);
   gimp_devices_add_widget (shell->display->gimp, shell->vrule);
 
+  g_signal_connect (shell->canvas, "grab-notify",
+                    G_CALLBACK (gimp_display_shell_canvas_grab_notify),
+                    shell);
+
   g_signal_connect (shell->canvas, "realize",
                     G_CALLBACK (gimp_display_shell_canvas_realize),
                     shell);