I came across 2 issues with the plugin that happens even with the example cap.
The first is that when you go into full screen, the mouse seems to be locked to the previous window size. This can be worked around by disabling the mouselock, then re-enabling it.
The second issue seems to happen randomly. When I preview your cap file, I click on the viewport to activate the mouse lock. Then if I just move the mouse around for a few seconds, the cursor will jump locations. Any chance you could look into this?