I got reminded of this issue by this thread:

showthread.php?tid=17581

The things is, I like to have previews of my files. It's a great time-saver. And at the same time, I like to keep things consistent as far as possible which is why I have Dolphin configured to "Use common view for all properties". This works well in 99 % of the cases with one noteable exception: .desktop files, and that's most easily seen if you use the applications:/ kio-slave.

If "Previews" is turned on, KDE treats .desktop files as text-files (which, of course, they are). I'd rather always get a proper icon for whatever the .desktop file refers to as a preview instead of a text-only preview (which wouldn't make much sense for someone not knowing what a .desktop file is anyway) no matter if "preview" is turned on or off.

Can this be accomplished somehow?

It can for specific protocols, and I think directories. I do not believe it can be done for file types.

Protocols - in Konqueror: Settings > Configure Konqueror > File Management > Previews & Meta-Data. Ensure the protocols you do not want previews generated for ( applications for instance ) are unchecked. in Dolphin just select Previews & Meta-Data ( they both share this configuration )

Directories - Dolphin has a "Previews" button available. I believe if it is not selected then I do not think previews will be generated, regardless of the overall setting ( do not know if this works )