Hmmm... if you have tabs enabled in general, then I think it should be this option:
F2 > Window Diversion
Chose "open in new tab", then click on "Links meant to open a new window", switch to "passed from external applications", and check again "new tab"...
It has nothing to do with command line options, that's just the normal user preferences (F2) set for the browser in general.
But I think there was a macro somewhere, that sets all sorts of stuff to open in new tabs instead new windows... Ah yes, look in the macro library:
http://kmeleon.sourceforge.net/wiki/macrolibrary
It's named "Tab All Windows"
Edited 1 time(s). Last edit at 06/03/2011 10:09AM by siria.