Game paused and knocked me into the void

I was making a bridge in the End, i was holding shift down and moving backwards, suddenly my game paused and showed me a notice from Adobe Flash Player. For some reason this notification made the game pause while simultaneously dropping me off the bridge. When I resumed the game I fell into the void and lost all my belongings because of that notification. Could there be a fix to this where, when the game pauses, the player automatically stops moving for safety reasons?