Fix NPE in GestureManager if the user alt+tabs away and back while a drag gesture is in progress.
Fix NPE in GestureManager if the user alt+tabs away and back while a drag gesture is in progress.

osric-the-knight/foam,osric-the-knight/foam,foam-framework/foam,jlhughes/foam,osric-the-knight/foam,mdittmer/foam,foam-framework/foam,jlhughes/foam,foam-framework/foam,jlhughes/foam,foam-framework/foam,foam-framework/foam,mdittmer/foam,jacksonic/foam,jacksonic/foam,jacksonic/foam,osric-the-knight/foam,jacksonic/foam,mdittmer/foam,mdittmer/foam,jlhughes/foam