OK, so with debian/patches/061_multiarch_module_fallback.patch re-enabled I can confirm that applications work fine with Adwaita, but crash with Unico. If you are testing, build from the branch and install the packages but be prepared to have the old .debs to roll back to and the appearance preferences window open to switch themes (otherwise you can't start any GTK+ application if using Unico and the 3.5.2 packaging). I'm testing gcalctool, runs fine in Adwaita, and crashes with Unico: bob@alchemy:~/bzr/ubuntu/gtk+3.0$ gdb gcalctool GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2) 7.4-2012.04 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". For bug reporting instructions, please see: ... Reading symbols from /usr/bin/gcalctool...(no debugging symbols found)...done. (gdb) r Starting program: /usr/bin/gcalctool [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:86:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:193:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:229:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:292:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:326:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:413:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:749:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1097:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1190:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1202:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1292:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1725:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1827:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1844:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1860:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1922:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1931:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1945:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:2015:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:2147:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:19:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:96:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:186:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:506:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:853:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:928:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:944:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:960:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:1015:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:1023:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:1037:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:1106:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gtk-widgets-backdrop.css:1240:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: gnome-panel.css:94:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:14:18: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:14:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:77:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:82:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:111:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:117:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:122:21: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: nautilus.css:132:20: Not using units is deprecated. Assuming 'px'. (gcalctool:4476): Gtk-WARNING **: Theme parsing error: unity.css:23:21: Not using units is deprecated. Assuming 'px'. [New Thread 0x7fffee611700 (LWP 4479)] [New Thread 0x7fffede10700 (LWP 4480)] [New Thread 0x7fffecfdb700 (LWP 4481)] [New Thread 0x7fffdffff700 (LWP 4482)] (gcalctool:4476): Gtk-WARNING **: Style property "border-top-left-radius" is not gettable (gcalctool:4476): GLib-GObject-WARNING **: /build/buildd/glib2.0-2.33.1/./gobject/gtype.c:4206: type id `0' is invalid (gcalctool:4476): GLib-GObject-WARNING **: can't peek value table for type `' which is not currently referenced Program received signal SIGSEGV, Segmentation fault. 0x00007ffff7934267 in gtk_style_context_get_valist () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 (gdb) bt #0 0x00007ffff7934267 in gtk_style_context_get_valist () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #1 0x00007ffff797cd3a in gtk_theming_engine_get () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #2 0x00007fffeea237e3 in _gtk_rounded_box_apply_border_radius () from /usr/lib/gtk-3.0/3.0.0/theming-engines/libunico.so #3 0x00007fffeea254dc in ?? () from /usr/lib/gtk-3.0/3.0.0/theming-engines/libunico.so #4 0x00007fffeea26df8 in ?? () from /usr/lib/gtk-3.0/3.0.0/theming-engines/libunico.so #5 0x00007fffeea2bade in ?? () from /usr/lib/gtk-3.0/3.0.0/theming-engines/libunico.so #6 0x00007ffff7936156 in gtk_render_background () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #7 0x00007ffff79fce31 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #8 0x00007ffff789eabf in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #9 0x00007ffff79de9be in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #10 0x00007ffff6a6d353 in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 #11 0x00007ffff6a86af8 in g_signal_emit_valist () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 #12 0x00007ffff6a87232 in g_signal_emit () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 #13 0x00007ffff79e21cc in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #14 0x00007ffff79ed725 in gtk_widget_send_expose () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #15 0x00007ffff789e8b2 in gtk_main_do_event () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #16 0x00007ffff74b0b60 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0 #17 0x00007ffff74aff76 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0 #18 0x00007ffff74b023c in gdk_window_process_updates () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0 #19 0x00007ffff79fc977 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #20 0x00007ffff6a6d353 in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 #21 0x00007ffff6a86af8 in g_signal_emit_valist () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 #22 0x00007ffff6a87232 in g_signal_emit () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 #23 0x00007ffff7804183 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #24 0x00007ffff7492e90 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0 #25 0x00007ffff6455835 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #26 0x00007ffff6455b68 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #27 0x00007ffff6455c24 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #28 0x00007ffff6d4ed4c in g_application_run () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0 #29 0x000000000040d29a in main () (gdb) quit