Custom dialog settings don't apply to the dialog tray

Confirmed this works and sets the edit form width in the dialog tray correctly.

One small issue is that if something expands to fill the entire screen, it is then very tricky to get your preview area back again. The open/close form button is hidden and the grab handle to drag the form width smaller is pretty fiddly to target.

Automatically closed - issue fixed for 2 weeks with no activity.