Works just fine (as of kde-plasma 5.14 on Gentoo). I even got for it the original desktop icon from oxygen icon set.

Thanks a bunch. I’m so sorry that it has become so complicated to enable such a simple thing!

Choose “edit applications”. (Open KDE Menu Editor)

In the new window go to the “Utilities” section in the menu list. Click the little arrow at the left to open the list within.

Find “Show Desktop”. Click on it. In the right half of the screen at the top, click “advanced”.

Go to “current shortcut key” and click where it says “none”.

It will change to “input…”

Press and hold the Meta key and “D” (or whatever you want).

Click apply.

The first time I used the “show desktop button” it updated the plain icon to what I choose.

Next will be trying to find a way to bind a keystroke to it so I get the “Meta-D” functionality back that I had before.

I still love the KDE DE but I wished I had not upgraded my system to the new version b/c so many of my tweak evaporated in the process. I was really settled into the old version.

Your fix works a treat though! That has been my experience too – each update breaks some tweak that is part of how I use my computer and it takes time to get it back.