Reading a page on widget alignment from the Aqua interface guidelines helped me realize something that's been bothering me about the GNOME interface guidelines.
The GNOME guidelines give a suggested technical dialog box layout consisting of a series of nested boxes. The top-level box is a GtkVBox, with alternating rows for labels and control groups. The first row of the vbox should be the section header label. The next row should be a GtkHBox with a label as the left side element and a GtkVBox as the right side element. The label on the left should contain four spaces. Each row of the box on the right should contain controls logically associated with the given section header.
How can this possibly be localization-friendly for cultures that don't use left-to-right writing systems ? With a single vbox containing controls, it would be easier to localize (but probably harder to parse visually). But with the suggested layout, an hbox that contains a (generally anonymous) blank label on the left side will always indent the control groups away from the left edge. Indenting from the right, which one might want in Arabic locales, would require rearranging some of the GUI at the application code level. This doesn't seem like something that pango has any control over. I don't get it.
That said, I think the GNOME guidelines look really good, for my locale. :)