Made this small but fully configurable plasmoid whose sole purpose is to inject/manage the background of other widgets in the same panel, the goal was to replicate the famous WM status bar look without actually making other widgets or modifying the panel itself.
I think the result looks interesting for something that I figured out was possible just a couple days ago.
This is the first release so it may have some unexpected bugs
This is just a plasmoid I made for myself that does this (not something you will find in plasma 6 as a official feature, just to be clear). The only reason is plasma 6 only is because it’s what I use now but it should work there too if ported to 5.
Oh, sorry I got confused, for changing just the panel background (I think is what you mean by taskbar?) you just replace/modify the panel-background.svg inside the desktop theme (I think there are different variants of fit for opaque and translucent and maybe some other), no other plugins like this one are needed for that.
After some months not wanting to touch the monstrosity that v0.5.x became, I decided to rewrite most of the widget, took me a month and some things still need to be worked on, but it’s in a (hopefully) more stable state now.
Release highlights
Revamped preset management, built-in presets, preset preview (spectacle needs to be installed for preview creation)
Faster initialization and more reliable
Survives and doesn’t break with Edit Mode (dragging, adding, removing widgets)
Configuration overrides, apply a different configuration for one or multiple widgets, either for the preset or personal