When you implement an own TabbedComponentFactory and uses JTabbedPaneAdapter the same problem arises as it is described in bug #199311 ("when I try to use the mouse to drag the scrollbar of any TC - editor, explorer-type, Bugzilla, profiler snapshot - which is docked normally (editor mode or not), the scrollbar moves briefly but then stops; the cursor changes to the "drag" icon (arrow plus box); and a red drag outline appears around the window, all as if I had initiated a drag on the title bar").
I have traced it to JTabbedPaneAdapter.tabbedImpl.getTabsArea (). It returns the bounds rectangle of the entire JTabbedPane, not just the headers part.
In my hack, I changed getTabsArea () to the following:

public Rectangle getTabsArea() {
Rectangle r = getBounds();
r.height = 0;
if ( getTabCount() > 0 ) {
TabbedPaneUI ui = getUI();
for ( int i = 0; i < getTabCount(); i++ ) {
r = r.createUnion(getUI().getTabBounds(JTabbedPaneAdapter.this, i)).getBounds();
}
}
return r;
}

Maybe not the best solution, but ...

Best regards,
//Zeljko