STORM-1016 FIXED Crash after pressing ctrl-shift-w while there is an undocked sidepanel.

Reason: The shortcut closes all floaters, including those wrapping undocked sidepanels.
The sidepanels get destroyed as well, while they are still referenced by the side tray.

Fix: Dock (i.e. move to side tray) the sidepanel before its floater gets destroyed.