Why does the screen flash everytime I add, remove or edit a slider or button, or do a Rebuild?

Your compiler must momentarily be brought to the front while RackAFX modifies the code; this actually has to do with how RackAFX automatically saves your work before modifying it.

How can I make the screen stop flashing when I add, remove or edit a slider or button, or do a Rebuild?

Keep your compiler minimized. In the minimized state, it does not need to be brought to the front in order to receive commands from RackAFX. You can always restore the compiler window and bring it to the front by using the “->C++” button in the button control bank on the right.