I doubt the problem is caused by having a maximized window because usually even
a maximized window will go behind another if you pull the other window up on
top
of it. I am having the same problem and it doesn't matter if it is maximized or
not. Also, the taskbar is not being covered up by Outlook, it is just other
windows that are opening behind it, so that doesn't fix it either. It sounds
like the previous replier might have been picturing it going into full screen
mode or something instead.
I finally found the following thread that helped me. I'm not exactly sure what
caused mine to start staying on top (I just installed Google Drive, so maybe
that changed something because I read a lot about it being caused by add-ons in
other threads), but this was super easy and quick, and it fixed my problem
immediately.
http://www.techtalkz.com/microsoft-outlook/138776-new-mail-window-always-top.html
(This link might be helpful too for those who aren't sure how to run the
command
that the above link recommends:
http://office.microsoft.com/en-us/outlook-help/command-line-switches-HP001003110.aspx)
I also saw on other sites some people say that it works to just right-click the
taskbar and toggle the "Lock the Taskbar" setting on and off. This
didn't work for me though.