I've noticed this anomaly using Psi, although once or twice it happened with
another applications. The problem is with appearing of new dialog windows,
being children of already running applications.
The window (in my case the Psi chat dialog) pops up at the top of all windows
on the current desktop, however it doesn't have a focus, thus after pushing
twice <alt><tab> it's at the bottom of the current desktop.
Before upgrading to 4.1.90 I was using a CVS snapshot from ca. beginning of
the August and it never happened.
It is rather minor problem, but it's a pain in the ass.
That's the stealing focus mechanism, the applications (or its toolkit) prolly
don't update their _NET_WM_USER_TIME (and xfwm4 don't give focus to windows
whose _NET_WM_USER_TIME is older than the last event time)
BTW, I've now added a new hidden option "prevent_focus_stealing" (disabled by