Not create new message while keep mouse wheel scrolling

[RuBing-Yang]

I usually use KeyCastOW for presentations or meetings, and when i keep my mouse wheel scrolling up or down to turn pages, the messages would quickly cover the full screen. Then my content would be blocked, that’s kind of inconvenient.

My changes were pushed on the fork KeyCastOW_modify

(Not a native English speaker, sorry if i make grammar or spelling mistakes)