http://bugs.winehq.org/show_bug.cgi?id=23108
--- Comment #16 from alister.hood@gmail.com 2013-07-03 18:58:19 CDT --- The behaviour seems to have changed in 1.6rc4. Excel is only shown once in the taskbar and alt-tab. So the user needs to use "View-Window-Switch Windows" (or presumably the built-in keyboard shortcut) to switch between the files. Behaviour of Word (as described at bug 31298) is unchanged - switching via window manager or taskbar works, but the Switch windows feature doesn't work. I suspect this is a completely unrelated issue.