@erincandescent @dalias @mcc @whitequark @becomethewaifu I'm talking about dragging *windows*.
As in, you have a toolbar or something that's within an application, not a WM-managed-window, and you want to drag it out and make it a free floating window, or drag it into another window and make it part of the app window again.
This involves knowing relative positions of all of your app windows, the dragged window, the cursor, etc.