Mouse mode is ignored when game is run on emulator

[LMNTreePenguin]

Wrote a quick pong game that uses mouse x and y to operate paddles. Mouse mode should be captured and works on windows. But when run on the Pi3+ with retropie mouse cursor is visible and not centered. So I don't know if retropie is drawing a mouse cursor on top of the game or if it's a video issue. Using GLES2.

I can send the pck if you need.