bug#16028: 24.3.50; Latest build completely breaks my thumnail frames code

[Eli Zaretskii]

> Date: Fri, 06 Dec 2013 19:57:09 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: drew.adams@oracle.com, 16028@debbugs.gnu.org
> 
> x_set_font does a lot to make redisplay happen.

You mean the call to clear_current_matrices?  AFAIR, that's not
enough: it just ensures that _when_ redisplay happens, every screen
line will get redrawn.  But it doesn't force redisplay.

Perhaps try calling fset_redisplay for that frame.