Created attachment 35984 [details] [review]
patch

Removed colormap in on_expose_event()

Made it draw something nice.

Is this patch meant to fix the crash reported bug 163992? 

No it's not, it's meant to make the example work.
I just discovered bug 163992 while working on this, this patch does not fix 
that, just the example.

1. This patch contains whitespace changes. Please try to remove them so I can
more easily see what has really changed.
2. This patch does more than just what it says in the ChangeLog. Please explain
them.
3. If this patch contains a workaround for another bug, then please wait until
that bug is resolved and/or clearly comment-out that code so that it can be
re-enabled later.

By the way, the gtkmm book gets the code directly from the examples directory,
so it is not necessary to also patch the book.

Created attachment 36097 [details] [review]
cleaned up patch

1. done that
2. done that
3. Using modify_bg and modify_fg is not really a workaround for bug 163992
although this made it crash on my machine.
I just think this is a simpler way, and i did not think changing this would be
a problem because how we change the colors is not essential to this example.

Question: It doesn't seem to make a difference if on_expose_event() returns
true or false, what is this return value for and how is it used?

Excellent. Many thanks. Applied.