[Xmonad] transient windows and tabbed layout

Is it the intended behavior that when using the tabbed layout transient windows will remain even when switching away from the application's window? Or is the problem I am having that my software is not correctly hinting its windows? For example, when I am sending mail in Thunderbird it pops up a progress window. If I switch tabs, the progress window remains. This is not too bad in of itself, but what really annoys me is that whenever the progress meter refreshes, it switches me back to the Thunderbird tab that opened the progress meter window.