Bug 652629 - GnomeCanvas: Disregard synthesized crossing events

synth_crossing() in gtkwidget.c does not set valid pointer coordinates,
but GnomeCanvas relies on these coordinates to figure out what canvas
item the event applies to.

Detect these synthesized GDK_ENTER_NOTIFY and GDK_LEAVE_NOTIFY events
and disregard them.

This was breaking drag-and-drop of EMinicards and probably elsewhere.

1 files changed, 7 insertions, 0 deletions

diff --git a/libgnomecanvas/gnome-canvas.c b/libgnomecanvas/gnome-canvas.c
index a0ad066f44..cca3df0e56 100644
--- a/libgnomecanvas/gnome-canvas.c
+++ b/libgnomecanvas/gnome-canvas.c
@@ -2736,6 +2736,13 @@ gnome_canvas_crossing (GtkWidget *widget, GdkEventCrossing *event)
 	if (event->window != bin_window)
 		return FALSE;
 
+	/* XXX Detect and disregard synthesized crossing events generated
+	 *     by synth_crossing() in gtkwidget.c.  The pointer coordinates
+	 *     are invalid and pick_current_item() relies on them. */
+	if (event->x == 0 && event->y == 0 &&
+	    event->x_root == 0 && event->y_root == 0)
+		return FALSE;
+
 	canvas->state = event->state;
 	return pick_current_item (canvas, (GdkEvent *) event);
 }