Found with scan-build.
https://bugzilla.gnome.org/show_bug.cgi?id=712760
GdkWindow *composited;
GdkWindowPaint *paint;
GdkWindowImplClass *impl_class;
- GdkRectangle clip_box;
+ GdkRectangle clip_box = { 0, };
cairo_region_t *full_clip;
cairo_t *cr;
touch_grab = _gdk_display_has_touch_grab (display, device, sequence, serial);
grab = _gdk_display_get_last_device_grab (display, device);
+ /* Default value. */
+ if (evmask_out)
+ *evmask_out = 0;
+
if (is_touch_type (type) && pointer_emulated)
{
switch (type)