according to the last post of this thread : https://forums.uberent.com/threads/reproduction-of-cursor-bug.50898/page-2 the post is a bit old, so I'm not sure it's still 100% accurate : one of the dev said:"For the cursor we use the standard XCursor library with calls like XcursorImageLoadCursor. We could hide the system cursor and compose the cursor image ourselves but that has a couple of downsides, primarily that it adds more lag between when the mouse moves and when the cursor moves."