protected void installDragAndDropSupport(DatabaseNavigatorTree navigatorTree) {
        // Add drag and drop support
        NavigatorUtils.addDragAndDropSupport(navigatorTree.getViewer());
    }
This is a callback that will allow us to create the viewer and initialize
it.
plugins/org.jkiss.dbeaver.ui.navigator/src/org/jkiss/dbeaver/ui/navigator/database/NavigatorViewBase.java