Val,
This my be a stupid thing to suggest, but do you still have the notation showing as well as the Tab? I had a bit of a look round the program and there isn't really an option I could find that let's you remove/display a time sig...
If you have no Notation on, go file > Show standard notation. Nothing else in the view file seems to be of any use here... Other than that, it may just be a glitch in the program... Maybe try re-installing it?
Or download the demo version from the site and see if that works...
Dunno mate...
Good luck with it
Dan