There is an old debate I see you found here:
http://bugzilla.gnome.org/show_bug.cgi?id=97061My personal preference here would be to support the
attributes property in glade, as proposed by Matthias.
Then the preffered way of setting markup would simply
be through a separate property. (the bug also mentions
certain conflicts when setting "attributes" & "use_underline"
and other auxiliary properties, these conflicts IMO should
be dealt with in
gtklabel.c).
Cheers,
-Tristan
PS: Adding glade-devel to the CC list, hope thats ok.