Hi,

Thanks for taking the time to report this issue. I managed to reproduce this earlier in the 1.40b build and found it to be a recently introduced regression caused by the new 'Terminate test runner tasks when all test execution is complete' configuration setting. If you turn this setting off, the button should start working again.

The upcoming 1.41b release contains a fix that should resolve this issue properly if you want to work with the configuration setting enabled.

It's interesting that moving to Windows 7 solved the localisation issue for you. I wonder if the change to the new O/S could have somehow changed your language settings in a way that worked around the problem. I did manage to reproduce the issue myself on Windows 7 but could find no way to fix it without completely replacing the visual component itself (a very expensive exercise).