@unlimitedbacon Debian Wheezy 7.1. I also have it running on another machine (Debian 8.8) and it runs fine except if you need to flip the part over it won't come out of edit mode and it doesn't save - even tho it says it did. The file that was queued also disappears when you hit save.
I'm having the same problem. The dialog is not hidden, it's not even opening. When running from a terminal, here's what I get when I click on Add:
(process:23581): GLib-GObject-CRITICAL **: /build/buildd-glib2.0_2.33.12+really2.32.4-5-i386-eISom6/glib2.0-2.33.12+really2.32.4/./gobject/gtype.c:2722: You forgot to call g_type_init()
(process:23581): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed
(process:23581): GLib-GObject-CRITICAL **: /build/buildd-glib2.0_2.33.12+really2.32.4-5-i386-eISom6/glib2.0-2.33.12+really2.32.4/./gobject/gtype.c:2722: You forgot to call g_type_init()
(process:23581): GLib-GObject-CRITICAL **: /build/buildd-glib2.0_2.33.12+really2.32.4-5-i386-eISom6/glib2.0-2.33.12+really2.32.4/./gobject/gtype.c:2722: You forgot to call g_type_init()
(process:23581): GLib-GObject-CRITICAL **: /build/buildd-glib2.0_2.33.12+really2.32.4-5-i386-eISom6/glib2.0-2.33.12+really2.32.4/./gobject/gtype.c:2722: You forgot to call g_type_init()
(process:23581): GLib-GObject-CRITICAL **: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed
(process:23581): GLib-GObject-CRITICAL **: /build/buildd-glib2.0_2.33.12+really2.32.4-5-i386-eISom6/glib2.0-2.33.12+really2.32.4/./gobject/gtype.c:2722: You forgot to call g_type_init()
(process:23581): GLib-GObject-CRITICAL **: g_type_interface_add_prerequisite: assertion 'G_TYPE_IS_INTERFACE (interface_type)' failed
(process:23581): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed
(process:23581): GLib-GObject-CRITICAL **: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed
(process:23581): GLib-GObject-CRITICAL **: /build/buildd-glib2.0_2.33.12+really2.32.4-5-i386-eISom6/glib2.0-2.33.12+really2.32.4/./gobject/gtype.c:2722: You forgot to call g_type_init()
^C
At that point I had to hit Control-C as the program was locked up.