Esc: Cancels a drag operation, but does not revert to the initial state. I.e. when you start dragging a window and press Esc, this window will not revert to its original state, but will remain as it is at the moment of pressing Esc.
Double click: Double-clicking the title bar of a ToolWindow un-docks the panel so that it floats. Double-clicking the title bar of a floating window docks the ToolWindow.