Loading Screen won't go away without mouse movement.

Dear all, I’m having a bit of difficulties here hope someone can help out.

I’m using FLoadingScreenAttributes for loading screen, I need to call StopMovie() myself, can’t let it go auto complete. So I added in the options:

bAutoCompleteWhenLoadingCompletes = false
bWaitForManualStop = true
bAllowEngineTick = true

Everything works fine, except that the loading screen won’t go away until mouse movement is detected. Any idea how to fix this? Thx.