Created attachment 110342 [details]
test case

In the attached testcase, you'll see that Ive set "weight" to be bold
and "weight-set" to sync with ATTRS_COLUMN_IS_TITLE.

When you compile without -DTREEVIEW_WAS_WORKING then no child iters
are added and the titles are bold, if you compile with the said flags
it will add a child iter that is not flagged to be bold, and this 
causes the parent iters to also lose boldness.

Ok, thanks to Mitch I found the proper way to set attributes is
to skip the "attrib-set" properties alltogether and sync the values
of the "attrib" properties themselves to appropriatly typed values 
in the corresponding store.

Heaping this into "doc" bugs, this usage should be better documented.