On Mon, 25 Sep 2017 10:01:30 +0900, Katsumi Yamaoka wrote:
> Emacs screen often becomes blank or blinks.  This didn't happen
> the last weekend, doesn't happen sometimes but often happens.
> Changing the window configuration --- scrolling a window, showing
> a message of two or more lines in the echo area, etc. --- seems
> to cause it.  More funny thing is, when two Emacsen are running,
> the one of which the frame is not selected becomes blank.
> Typing any key in the selected blank frame will help, as if
> (sit-for ∞) is running.

Reverting the change c0af83b[1] solves this problem.

[1]
Don't attempt to disable double buffering in newer GTK+ versions
<http://lists.gnu.org/archive/html/emacs-diffs/2017-09/msg00293.html>