KateMDI: sidebar and focus...

Since KDE 3.5.5 Kate has its own MDI implementation. It is similar to KMDI but ships with a lot less bugs (yes, and features). One thing bothering me is the focus issue: Which sidebar has the focus? If you do not know, you have to have sharp eyes to find out. In KDE4 I just hacked in such a feature (here is the patch). On the screenshot you can see that every sidebar now has an additional pane on the top. Unfocused sidebars have a gray pane (default window background color), a focused sidebar has a blue pane with white text (just like selected text). Which sidebar has focus? - Right, it's the Documents sidebar :) It work's pretty well, so is it worth committing (a cleaner version of) the patch? I initially hoped that QDockWidgets would provide this functionality by default. Similar discussions take place on kde-core-devel as well (about KTabBar & friends)...