Add an entry about fonts and colors problems on KDE.

etc/PROBLEMS

@@ -461,6 +461,30 @@ be done _after_ turning on Font Lock.)
 Another alternative is to avoid a paren in column zero.  For example,
 in a Lisp string you could precede the paren with a backslash.
 
+* When running on KDE, colors or fonts are not as specified for Emacs,
+or messed up.
+
+For examlpe, you could see background you set for Emacs only in the
+empty portions of the Emacs display, while characters have some other
+background.
+
+This happens because KDE's defaults apply its color and font
+definitions even to applications that weren't compiled for KDE.  The
+solution is to uncheck the "Apply fonts and colors to non-KDE apps"
+option in Preferences->Look&Feel->Style.
+
+Alternatively, if you do want the KDE defaults to apply to other
+applications, but not to Emacs, you could modify the file `Emacs.ad'
+(should be in the `/usr/share/apps/kdisplay/app-defaults/' directory)
+so that it doesn't set the default background and foreground only for
+Emacs.  For example, make sure the following resources are either not
+present or commented out:
+
+   Emacs.default.attributeForeground
+   Emacs.default.attributeBackground
+   Emacs*Foreground
+   Emacs*Background
+
 * Interrupting Cygwin port of Bash from Emacs doesn't work.
 
 Cygwin 1.x builds of the ported Bash cannot be interrupted from the