This was on purpose to allow improperly coded KDE applications to show up, for instance synaptic will not work otherwise as it uses OnlyShowIn=KDE.
The problem is identified in bug report 1364.
I understand how this dual test was added after 3.5.10, when TDE was still considered KDE. Now that TDE is a recognized standalone XDG desktop, the dual testing for both TDE and KDE should be removed in R14.0.0.
I don't know that the change should be backported to 3.5.13.x, but the change is needed in R14.0.0.
Darrell
We would need upstream acceptance of TDE in affected projects for this to be viable. If this is not done, then users will notice a degraded experience when basic programs such as Synaptic cease to function properly. These users would then note that such applications work properly under KDE, and logically conclude that TDE is broken.
I think this is a lesser of two evils problem, and would like to keep the dual test in at this point.
Thoughts from others knowledgeable in this area?
Tim