Mouse Stops Working until Save

[malee]

I have a consistent problem with my Sibelius software that happens every time I work with the program.

Every few minutes, the mouse will no longer allow me to click. I can move it, and it will track my position on the screen, but if I click to select or to grab and move the score, it won't respond to my clicks. Once I hit save, it will then allow me to click once again. It happens this way every time.

It's not fatal, but it is annoying enough to interrupt my work flow. Any suggestions would be very helpful.

Here's what I'm running:

MacPro 8-core 2.8 GHz
4 GB ram, 500 gigs of open space on system drive
OSX 10.6.3
Sibelius 6.1.0 build 14
Logitech Marble Mouse (but it does the same thing with other mice)