osx_missioncontrol_window_hidden_glitch

diff --git a/intern/ghost/intern/GHOST_WindowCocoa.mm b/intern/ghost/intern/GHOST_WindowCocoa.mm
index 9e47ea1..9a01885 100644
--- a/intern/ghost/intern/GHOST_WindowCocoa.mm
+++ b/intern/ghost/intern/GHOST_WindowCocoa.mm
@@ -68,6 +68,7 @@ enum {
 - (void)setSystemAndWindowCocoa:(GHOST_SystemCocoa *)sysCocoa windowCocoa:(GHOST_WindowCocoa *)winCocoa;
 - (void)windowDidBecomeKey:(NSNotification *)notification;
 - (void)windowDidResignKey:(NSNotification *)notification;
+- (void)windowDidBecomeMain:(NSNotification *)notification;
 - (void)windowDidExpose:(NSNotification *)notification;
 - (void)windowDidResize:(NSNotification *)notification;
 - (void)windowDidMove:(NSNotification *)notification;
@@ -93,6 +94,11 @@ enum {
        systemCocoa->handleWindowEvent(GHOST_kEventWindowDeactivate, associatedWindow);
 }

+- (void)windowDidBecomeMain:(NSNotification *)notification
+{
+       // ignored
+}
+
 - (void)windowDidExpose:(NSNotification *)notification
 {
        systemCocoa->handleWindowEvent(GHOST_kEventWindowUpdate, associatedWindow);