In xfdesktop-settings, on the Icons tab, when I try to activate the Icon _type: dropdown or the Icon _size: spinbox, I get the following on the console: (xfdesktop-settings:5373): Gtk-WARNING **: widget `GtkVBox' isn't suitable for mnemonic activation
Can't reproduce this here. gtk version? libglade version?
This happened on Ubuntu Jaunty, with Xfce 4.6.0, and libgtk 2.16.1, libglade 2.6.4. Perhaps it's already fixed... if pressing the Alt+t, Alt+s shortcuts activate the dropdown/spinbox, then it's ok to close this bug.
Ah, you didn't say anything about using the keyboard. Please try to be more specific. I see the same problem when using the keyboard.
Fixed in master and xfce-4.6 branch