xorg-server-1.4.2-alt10.M41.1
libpixman-0.32.4-alt1
libXrender-0.9.6-alt2
wm-select-0.8-alt1
firefox-10.0.7-alt0.M50P.2

I'm not sure whether this bug would be seen if I had X libs and clients from branch 4.1, too, but I have upgraded them.

All things worked before I upgraded to xorg-server-1.4.2-alt10.M41.1 : then, most fonts became displayed invisible (e.g., wm-select dialog, firefox menus, firefox rendered pages, etc.). They become visible when I hover over them, sometimes.

For a long time, I couldn't figure out where the bug was (whether it's new X libs and clients being incompatible with an old X server, or what?.. fortunately, the text was visible in Emacs buffers and urxvt, and that was enough to use this system).

Now, I have understood that it's a buggy extension that was automatically enabled in the old version of X server. I've inserted the following into /etc/X11/xorg.conf :

Section "Extensions"
	Option      "RENDER" "Disable"
EndSection

and the X clients have visible fonts again.

I'm using X on an Intel video card.

I'm attaching the log from the server that doesn't show text (fonts) correctly.

Either the Render extension should be disabled or fixed.