Menu Bar erratic disabling for unknown reason

When I close out the 2nd tab when browsing, the File, Edit, View toolbar will
become disabled. If I have three or more tabs, as I close the tabs everything
is fine until I get to the second (next to last) tab. Closing this tab will
result in the "greying out" or disabling of the menu bar, some percentage of
the time. Not 50% but often enough to be annoying, and as is usually the
case, right when you want to save or print something.
Anyone know why this happens and more importantly, how can I resolve this
issue?