[Bug] Windows lag when dragged, allowing the cursor to grab and drag another object

[Crimsonum]

When dragging a window around, it lags a bit behind the mouse cursor. If dragged fast enough, the cursor exits the window frame, and if the cursor touches another window or a map object, that object will be dragged instead. This bug means you can accidentally move objects in the map without noticing, if you're not careful when moving windows.

Example.