Hi, Panel Colorizer maintainer here, do you mean something like this?
What’s happening here:
- Each panel has two presets, one where there is no panel background but widgets do have background + blur, the other does have panel background and a different color/shape for widgets
- Bottom panel uses another pair of presets, one that sets the panel to fit-content mode and other that sets it to fill mode
- To get the spacers to shrink in the bottom panel when in fit-content mode I had to add such feature to a fork of the built-in panel spacer GitHub - luisbocanegra/plasma-panel-spacer-extended: Spacer with Mouse gestures for the KDE Plasma Panel featuring Latte Dock/Gnome/Unity drag window gesture. Run any shortcut, command, application or URL/file with up to ten configurable mouse actions. · GitHub with the built-in spacer the panel won’t shrink
- Panel colorizer creates widget islands using another widget as separator, see Panel Colorizer for Plasma 6 - #52 by luisbocanegra for an explanation of how that’s done
It is not perfect but it gets the job done