Please describe the problem:
Although it is possible to set/unset the use of e.g. "background" with "background-set", this is not possible for e.g. "family", "style", "weight".


According to the Subversion changelog this is not intended:
Revision 4843, Tue Sep 25 11:22:23 2001:

    * gtk/gtkcellrenderertext.c gtk/gtktexttag.c: Restore
      the behavior where you could turn family_set (etc) back on
      and get back the values you had before.



Steps to reproduce:
1. set "style" on a GtkCellRendererText to PANGO_STYLE_ITALIC
2. create a GtkTreeViewColumn with that renderer and set attribute "style-set" to a G_TYPE_BOOLEAN column


Actual results:
The style will be PANGO_STYLE_NORMAL as soon as "style-set" is set to FALSE and won't change to PANGO_STYLE_ITALIC.

Expected results:
Style should change according to the value of the G_TYPE_BOOLEAN column between PANGO_STYLE_ITALIC and PANGO_STYLE_NORMAL.

Does this happen every time?
yes

Other information:
To unset the font attributes pango_font_description_unset_fields() is used.
According to
http://library.gnome.org/devel/pango/unstable/pango-Fonts.html#pango-font-description-unset-fields
in current versions of Pango "The unset fields will get back to their default values."

Similar code is used in gtktexttag.c.


I'll attach a patch for gtkcellrenderertext.c with a possible solution:
I keep a private PangoFontDescription with all set properties and restore the attributes from it. Please have a look.