4a7e2ddff5
This call just went through stomping over previous drag operations if any, _maybeStartDrag() accounted for this, but other callers (well, WindowClone in workspace.js) don't. This must bail out early even if a drag operation is requested, luckily all callers account for it already. This broke shell state by preserving connected captured-event handlers if one tried to drag multiple windows simultaneously through multitouch. We of course don't support that, now more elegantly. https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/455