Stop using libglade GtkOptionMenu -> GtkComboBoxText move is to make porting to gtk3 easier (this needs gtk+ 2.24), most of the pixbuf changes in src/preview.c for the same reason. Other changes should not go beyond 2.18. The changes in packing in glade file are also for the sake of gtk3 - they shouldn't affect gtk2 (hbox51 removal was mostly to make things cleaner - there didn't seem to be a reason for extra container there). The added catch is that http://savannah.gnu.org/bugs/?34506 was only fixed in gettext 0.18.3 (just a few weeks old) and there's a little problem with gtk2 version of glade (http://bugzilla.gnome.org/show_bug.cgi?id=689667). The ui file itself nevertheless works.
Remove deprecated/unknown swapped value from .glade
Make the copyright message not translatable
Add a --tab option to switch to a specified tab on startup. (Bug 4797)
Allow margins up to 10000 in obconf (Bug 3601)
Fix video icon and shorten the window a bit
Remove the center placement option, and add Primary monitor to the monitor placement choices. The former is to match changes happening in openbox git. The latter is something that happened already in 3.5.0.
don't use a non-zero page size for some spinners (Fix bug #4540)
Add the Inactive OSD font, and the primaryMonitor options
add a nice decription of what the dock is
fix the "fixed popup position" options - the text was wrong for the fixed y position popup (using left/right instead of top/bottom) - the config wasn't being loaded correctly for them
change the <active> option to the <monitor> option
simplify the Shade button's description
show what letters do what for the button order
reword the "where to place new windows" label to maybe be more clear
choose a better mnemonic for another label, since the tabs were split up
fix conflicting mnemonic
add widgets to let you set the moveresize popup's fixed position
make the tabs bigger, it looks better and is easier to use
split the moveresize tab's code out from window.c