Dragging UIButton locks UI.GetCursorPosition()

I tried to make a simple drag&drop system using UIbuttons, but pressing and holding down on top of a button stops UI.GetCursorPosition() from updating.

Setting the button click mode to precise almost works, but since there is no way to check for "mouse 1 release", you'd have to check player bindings which could be rebound, causing your drag&drop system to stop working for some people.

Is there a better solution than checking Left Button / ability_primary while dragging?