I was a bit surprised to find that the tooltips in the "Colorize
Display" dialog box had a gray background, unlike the light-yellow
background tooltips from the other (X and non-X) toolkits/applications
I've seen.
The message
http://www.gnome.org/mailing-lists/archives/gtk-devel-list/
1999-October/0033.shtml
in the "gtk-devel" mailing list discusses this; Owen Taylor says:
First, the color of the tooltips is not something a program should
be changing under almost any circumstances. The color of the
tooltips is a perogative of the user / theme designer. Yes,
the default gray isn't very nice; the GTK+ packages we distribute
at Red Hat include the following in $sysconfdir/gtk/gtkrc.
=====
style "gtk-tooltips-style" {
bg[NORMAL] = "#ffffc0"
}
widget "gtk-tooltips" style "gtk-tooltips-style"
=====
No, I've no idea why
1) at least some widgets *other* than the tooltips widget appear
to get non-gray backgrounds (the CList, tree, and text
widgets in the three panes of the Ethereal display, and text
boxes into which you can type stuff, get white), but the
tooltip widget doesn't;
2) they don't supply a default "gtkrc" in the GTK+ source if
"the default gray" really "isn't very nice" (i.e., why they
didn't pick up what Red Hat did).