F2 rename shortcut stopped working on KDE 5 Plasma desktop

I recently installed Kubuntu 16.04 (KDE 5 Plasma) on a new PC and have been doing a lot of customisations, and I just noticed that the F2 shortcut for renaming files is not working on the desktop. It's still working in Dolphin.

Interestingly, the context menu for a file in Dolphin shows "Rename... F2", but on the Desktop, it just says "Rename" (no shortcut). The permissions are fine (755), and in fact, if I open the Desktop folder through Dolphin, F2 renaming works.

I thought it's probably some setting I messed up and I would easily find an answer on the Web, but I can't find anything useful/relevant (including this on askubuntu).

• Widgets and icons on the desktop are unlocked.
• Folder View Settings (from Desktop context menu) > Location is set to "Show the Desktop folder".
• I've searched through Global, Application and Custom shortcuts in case F2 was set to something conflicting but couldn't find anything (again, it works in Dolphin).
• I've tried tweaking other things (such as changing Wallpaper Type from Haenau to plain colour), but nothings seems to have an effect.

I'm listing random things right now because I cannot think what could possibly be the cause of this. Any ideas would be greatly appreciated.

System:

• KDE Plasma 5.5.5
• Qt 5.5.1
• Kernel 4.13.0-32-generic #35~16.04.1-Ubuntu 64-bit

I'm using Kubuntu 16.04 but with a newer version of Plasma: KDE Plasma 5.8.8 (Qt 5.6.1). For this reason, my answer may not apply to you.

Please check via System Settings > Shortcuts that you do have F2 selected for renaming files as shown in the image below. On my system, I can rename files visible on the desktop using F2.