One thing that might help you see what is going on. Their is an application inside your Utilities folder inside your Applications folder called Console.app. Have it running in the background and clear it's log, then attempt to reproduce the issue and see if you get a clue as to why this is happening. Also you might try to check your preference files. These are XML files that can, at times, get corrupted, this although unlikely, could be a culprit also.