How is this a KDE problem?

sorry i should have specified, but I was referring to KDE's coloring of non-KDE apps

I would like to add that the GTK file navigation has become unusable (under KDE)  I realize this is NOT a KDE problem but since KDE uses GTK extensively for its apps, someone with a large club should attack the GTK way of doing things.  Currently, running KDE 3.5.3 on SuSE 10.1, the file navigation windows appear to have 'shading' applied in this latest release.  In my case, that 'shading' is total black such that I can only read every other line.  Not Usable!!

</rant on>
Add to the above that I think the design of the GTK file navigation system is abominable and far from intuitive for normal users and I wish the whole thing would be chucked in the trash.  <\rant off>

KDE does not use GTK extensively for its apps. The only applications that use GTK are GTK applications, not KDE applications.

I've had the same problem here for a long time, with the last several versions of KDE (currently SUSE 10.1, KDE 3.5.5).  The KDE color settings are applied to GTK2 apps except that the menu foreground color does not change when highlighted like it should, making dark selection colors unusable.  This doesn't happen when running GTK apps under GNOME or certain other window managers (although in that case a different, GNOME, theme is applied), so it does seem to have something to do with the way KDE applies colors to GTK2 applications.

This would be a problem with the gtk-qt-engine software, not KDE. 
http://gtk-qt.ecs.soton.ac.uk/

Are you sure? I don't even have gtk-qt-engine installed. I'm talking specifically about the “apply colors to non-KDE apps” checkbox in System Settings > Colors. I've looked at the resulting generated gtkrc, and it simply misses the menu foreground color item. Having it include this item would fix this issue, which still exists to this day (I'm quite frankly surprised more people don't report it. It makes dark KDE themes totally unusable with GTK apps).

Travis, could you be more specific which items are generated (so that I can find the code responsible), and which items are missing? Maybe I can add them.

Thanks--I'm admittedly not too familiar with the gtkrc-2.0 file format, so it's possible I'm wrong about this.  I seem to remember being able to manually edit the file to make the menu selected foreground correct to temporarily fix the issue, though more recently my attempt to do this failed because I don't really understand the format of the items or which one corresponds to the menu color foreground.  I could attach a generated gtkrc-2.0 for a color scheme that fails to work properly; perhaps this would help pinpoint it.

Okay, I think I finally found it. In ~/.kde4/share/config/gtkrc-2.0, I have a set of lines near the bottom of the file that look like:

style "MenuItem"
{
  bg[PRELIGHT] = { 0.490, 0.039, 0.039 }
}

There is no entry for fg[PRELIGHT], so all highlighted menu items in a menu always show in black regardless of background, rather than using the entry from KDE's color settings (though highlighted items on the menu bar itself are okay). If I manually add the proper entry, it fixes colors in Firefox/Thunderbird, for instance.

Git commit 32d7d19aee2aa9ea910903217712325d33f733ea by Christoph Feck.
Committed on 14/09/2014 at 09:07.
Pushed by cfeck into branch 'KDE/4.11'.

Set foreground color for GTK2 menus
FIXED-IN: 4.11.13

M  +1    -0    kcontrol/krdb/krdb.cpp

http://commits.kde.org/kde-workspace/32d7d19aee2aa9ea910903217712325d33f733ea

Thanks Travis, I just committed a fix for the October release.

Git commit f658141e2d4704129b843cfad566029e380a47b0 by Christoph Feck.
Committed on 14/09/2014 at 18:50.
Pushed by cfeck into branch 'master'.

Forward-port krdb fixes from 4.11 branch

- Set correct Text foreground color on Base background
- Set foreground color for GTK2 menus

M  +2    -1    kcms/krdb/krdb.cpp

http://commits.kde.org/plasma-desktop/f658141e2d4704129b843cfad566029e380a47b0