I have a 4k screen and the Browser-based viewer window is centered in the middle of the screen, not taking up the whole screen.

When I move around in mouselook, the cursor all of the time escapes the viewer area and interrupts my mouselook experience.

Additionally, I am using multiple screens so there are additional screens around my main screen, so even if I zoom into the browser to make the viewer area cover all of the screen, the cursor keeps escaping to the monitors left, right and top.