I see that xdg-utils detects whether a KDE session is running by checking the equivlent between KDE_FULL_SESSION and true in every xdg-* utility. According to what a document in KDE's techbase describes, it'd better check whether KDE_FULL_SESSION is an empty string instead of a true value.

So, in each detectDE function in every xdg-* utility, following modification is better and stable for KDE's future possible change to variable KDE_FULL_SESSION.

if [ x"$KDE_FULL_SESSION" != x"" ]; then DE=kde;

Ref: http://techbase.kde.org/KDE_System_Administration/Environment_Variables#KDE_FULL_SESSION