Problem:

In the WASM target, the mouse event listener for mouseup was attached directly to the canvas element (canvas.onmouseup).

If a user clicks inside the canvas, drags the mouse outside the canvas boundaries, and then releases the button, the canvas element does not receive the event. This causes the application to miss the MouseButtonUp event and think the mouse is still held down.

Solution:

Changed the event binding in gl.js to listen for mouseup on the global window object instead of the canvas. This ensures the release event is caught regardless of where the cursor is (on and off the page).

Yes, this is the same issue as the one in the PR on macroquad, except this one is a web issue.

Hope this can get merged soon.