Hi. I tried to make Unity-like layout. I put one panel to the top (horizontal), and second to the left (vertical). I would like to make my top panel black (like Breeze dark theme), and keep my vertical panel white. Also I would like to set transparency level for my vertical panel. Is it possible to add such feature?
This exists if you modify your theme manually - you can specify a separate SVG for each side. See the section on prefixes here: https://techbase.kde.org/Development/Tutorials/Plasma5/ThemeDetails#Backgrounds_format As for adding it in the UI, it's too much of a niche feature that complicates both the code and user experience. Sorry.
I thought KDE philosophy is to make maximum tweakable DE. Thats what differ it from others. Almost all stuff in System Settings could be called "niche". You can set color for every graphical element (feature that majority of users don`t realy use), finetune visual effects, windows behavior, set wallpapers for each desktop individually (that is what realy complicate user experience - not to find wallpapers in System Settings). When global menu will be added to Plasma, many users will want to emulate Unity look by placing one panel to the top, other to left side as Dock for apps. And those people would want to tweak colors for each, to make them look different (now it just look horrible, when two panels merging in top left corner, so whole construction looks like monolith "Г" shaped frame). I believe wish to tweak panels colors much more natural for user when wish to tweak color for different text modes, or windows decorations. I was impressed how clean Plasma panels look as Dock. I thought I will use it instead of Plank. Seems like I have to use Plank again, so Plasma not differs much from many other DE`s in that sense... :(