Object Catalog was a floating window. It has been converted to a fixed
pane on the right hand side of the editor window. While it is a
BasicDockingWindow, at the moment it is not possible to undock, move,
or resize it. Also, the Object Catalog toolbar button does not show
the visibility status of the pane, ideally it should look pressed, when
the Object Catalog pane is visible. Another missing feature is that
the Object Catalog pane cannot be switched on together with the
dialog editor.