Bug 769419

**** Description of problem:
I run virt-manager (a gtk2 app) on my RHEL-5.7 workstation, and forward the output via "ssh -X -Y" to my laptop. My laptop was running fc14 until recently, and everything was fine. After switching to RHEL-6.2 on my laptop, the icons in virt-manager broke -- the trasparent parts are solid black. See more details below.

**** Version-Release number of selected component (if applicable):
gtk2-2.10.4-21.el5_7.7

**** How reproducible:
100%

**** Steps to Reproduce:
This needs two boxes, one with RHEL-6 and one with RHEL-5. There are four tests in total. On the RHEL-5 box, the "/usr/bin/gtk-demo" program is part of the gtk2 package. Under RHEL-6, it's in gtk2-devel. The problem affects other gtk2 programs as well (like virt-manager), but it's least convoluted to reproduce with gtk-demo.

Test #1: Start gtk-demo on RHEL-6, using the local (RHEL-6) X server. In the list to the left, double-click "Stock Item and Icon Browser". A new window appears. Scroll down to GTK_STOCK_OK. To the right, the icon is rendered in a big frame, and it's correct.

Test #2: Repeat the same on the RHEL-5 box, using the local (RHEL-5) X server there. Same correct results. (The gtk-ok image looks a bit differently, but the transparency is OK.)

Test #3: From an xterm running on the RHEL-5 display, log in to the RHEL-6 box with "ssh -X -Y", and start gtk-demo on the RHEL-6 box, forwarding its output to RHEL-5. The (correct) image to the right is identical to the one seen in #1.

Test #4: From an xterm running on the RHEL-6 display, log in to the RHEL-5 box with "ssh -X -Y", and start gtk-demo on the RHEL-5 box, forwarding its output to RHEL-6. You'll see the same Enter-like arrow icon as in case #2, but its transparency is wrong: it is surrounded by a pitch black square.

The images come from the following files (at build time):

2005-11-04 15:32:34 +0000     gtk+-2.10.4/gtk/stock-icons/20/gtk-ok.png
2009-04-02 13:54:56 +0000     gtk+-2.18.9/gtk/stock-icons/20/gtk-ok.png

I extracted their alpha channels with "pngtopam -alpha" to separate PBM files, and the alpha masks are correct.

**** Actual results:
RHEL-5 GTK apps forwarded to RHEL-6 X servers with SSH look weird.

**** Expected results:
Icons look identical independently of local or remote display.


Additional info:

[1] http://superuser.com/questions/327166/black-icon-backgrounds-when-using-ssh-x-to-run-remote-gtk-application
[2] http://fossplanet.com/f12/remote-x-renders-transparency-black-186866/