[xmonad] tabbed, floating & focus

Hello, I need a hint on how to fix a weird behavior of the Tabbed layout: imagine you have 2 windows in tabbed: A and B. A has focus. Now you call up a floating window C, like Scratchpad, and it takes focus. Then you move your mouse and, without hiding C, click on B tab, B gets focus. Now, if only you somehow give focus back to C (like drag the mouse over it) - tabbed will switch back to A. In the other words you can't switch tabs after you've added a floating window: as soon as floating gets focus again, tabbed restores it's state as it was before the floating window was added. It's quite annoying and I'd like to fix it, but X.L.Decoration logic is too complicated to me. Or maybe I should look at some other place?