In glade, create a spin button and then give it a maximum value of something greater than 100. Save the file and then open the glade file in a text editor and look at the <upper></upper> line...the value will be 100.
Upstream as http://bugzilla.gnome.org/show_bug.cgi?id=72924
Upstream bug fixed, need to get Glade 0.6.4 for the fix.
0.6.4 building now