FS9 Error

So, after the left turning problem, the next problem also arrives. Sometimes (happens randomly), the FS suddenly got into a critical error. The bar menu on the top (which i keep it unhidden) suddenly gone, there is a bar of freezed scene at the lowest part of the FS window, and you can't right clicking anywhere! even outside the FS (nor do i able to open any windows inside or outside FS).So, i have to hang it out by continuously clicking on the FS bar at the start bar, and then it can be closed (Task manager can't open when this is happening.)Anyone have a method to fix this one?Thanks a lot