Comment 7 for bug 331292

I added this in duplicate Bug# 331390, but here too for posterity:

I downgraded libgtk2.0 and everything is back to normal. The following list are interdependent, so I downgraded them all:

libgtk2.0-0
libgtk2.0-bin
libgtk2.0-common
libgtk2.0-dev
libgtk2.0-doc
libgail18
libgail-common
libgail-dev
gtk2-engines-pixbuf

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What I did was Ctrl-Alt-F1 to a terminal. Then I changed to /var/cache/apt/archives/

and then did:

sudo dpkg -i libgtk2.0-doc_2.15.3-0ubuntu2_all.deb libgtk2.0-common_2.15.3-0ubuntu2_all.deb libgtk2.0-bin_2.15.3-0ubuntu2_all.deb libgtk2.0-dev_2.15.3-0ubuntu2_amd64.deb libgtk2.0-0_2.15.3-0ubuntu2_amd64.deb gtk2-engines-pixbuf_2.15.3-0ubuntu2_amd64.deb libgail-dev_2.15.3-0ubuntu2_amd64.deb libgail-common_2.15.3-0ubuntu2_amd64.deb libgail18_2.15.3-0ubuntu2_amd64.deb

That's assuming you have those versions of the files in your apt archive.