(Besides the fact that scrollbar snapback breaks Fitts' law in spectacular ways and no toolkit on Linux besides Aura does it)

When you drag the scroll bar in a Chrome window (xwayland) and release the mouse button with the mouse outside the Chrome window whilst keeping the mouse close enough so it doesn't snap back, it will snap back to the previous scroll position nonetheless after you released the mouse.

1.) Open Chrome in a Wayland session and open some website
2.) Resize the window so there's a vertical scrollbar and make the window non-maximized (or add a top panel)
3.) Press and hold the scroll bar with the mouse
4.) Now scroll in any direction
5.) Move the mouse outside the Chrome window but keep it close enough so Chrome doesn't already automatically snap back
6.) Release mouse button

If the mouse hovers another X window (doesn't need to be a Chrome window, can be any Xwayland client, just stack it behind the Chrome window) then releasing the mouse while over that window won't snap it back.

It seems that the mouse release event doesn't get proper coordinates because X only gets the mouse position while inside an X client? Or don't we even set the X cursor back to 0,0 to ensure hover effects and what not reset?