I can confirm this bug, however it doesn't show up if compiz isn't used. That is, when compiz is enabled selecting "Only on this workspace" in Pidgin doesn't have any effect, it does when compiz is disabled.
I can confirm this bug, however it doesn't show up if compiz isn't used. That is, when compiz is enabled selecting "Only on this workspace" in Pidgin doesn't have any effect, it does when compiz is disabled.