I'm writing because there's a small 'feature' which annoys me and I wonder if it would be possible to resolve. Whenever I right click on the Hebrew Calendar status bar display and select either "Open Hebrew Calendar" or "Open hcalendar blog" I get a new instance of FF. I'd much prefer a new tab within the current instance. Is it possible to add this as an option?

see http://developer.mozilla.org/en/docs/XUL:Method:addTab