(1) extract method to call a panel method including the switch to the swing thread. Example: in DatabaseCheckController a very similar code block occurs 4 times.
(2) try to extract (abstract) base class for the panels
(3) review the separation of GuiDatabaseList into DatabaseListModel, DatabaseList (the view) and DatabaseListController according to the MVC pattern.
Note: Postponed after the release of 0.2 beta.