thank you to daniel, paul and sven for the suggestion to use Label.set_use_markup(True) and the pango markup language. not having encountered it before, i tried it out - unfortunately, it won't be sufficient. i made a fuller post last night (which got caught in the gtk-devel-list moderator bucket sorry) but the gist is that because the framework i am developing comes from an HTML/web background, it *must* be possible for users to place almost *any* kind of insane HTML into a widget - including things like < a href="javascript:False">Next< /a > - see the MailList.py example: http://code.google.com/p/pyjamas/source/browse/trunk/examples/mail/MailListp... so, that unfortunately rules out pango markup. running the KitchenSink.py example quickly showed two cases which failed: < code > and < div > are not supported by pango and they threw an exception. so, that leaves python-gtkhtml2, libgtkhtml3 (which doesn't have python bindings) and pywebkitgtk as the only options - all of which are presently flawed and not useable. i've spoken with Adrien Nader on #webkit and he kindly reviewed the webkit source code: function _do_ exist to pre-determine the size of the HTML content. these functions are _not_ utilised by pywebkitgtk which is a significant design flaw, and he was going to look at adding them to webkit's gtk interface. l.