1. Install a font with many styles - Gill Sans, for example
2. Open the GTK+ font selection dialog
3. Select each style and look at the preview pane

Gill Sans, for example, has lots of different styles: Light Shadowed, Light,
Light Italic, Regular, Condensed, Ultra bold, Extra Bold Display, Ultra Bold
Condensed, Extra Bold, Italic, Bold Extra Condensed, Bold Condensed, Shadowed,
Bold and Bold Italic. However, GTK+ does not use the styles correctly. For most
non-italic styles it uses "Ultra Bold" instead of the selected style etc.

I investigated this a bit and noticed that when selecting the styles that get
mapped to "Ultra Bold" (for example) the PangoFontDescription for the font
contains the same style, variant, weight and stretch values, so it isn't
surprising that the same style (Ultra Bold) is being used instead of the correct
style. Since I don't know GTK+/Pango/Fontconfig/FT2 very well I have no idea why
this happens, though. This is not a Fontconfig problem - at least I get what I
request for by using ft-match.

Versions: GTK+/GLib 2.4.4, Pango 1.5.0, Fontconfig 2.2.3 but this has been
present for a long time now.