Hi Lestat, you don't have to switch calendar to English: simply choose your language for the extension into it's options page. ;)
EDIT
Right Click on the Extension's Icon, choose Options and select the correct browsers calendar's pages language. I've got mine in italian and everything works correctly! ;)
98% Perfect! The 2%: I tried adjusting colours again after a while, but clicking the widget would not open it (?). A quick re-install opened the tab to change the colours again, so it was all good. But maybe you would like to that out? Either way good widget!
