An idea for a server side decoration and widget that allows app menus to be searched from the titlebar. This mockup shows what it might look like for Konsole. I used the Breeze Dark theme because the colors are more consistent.
Not entirely on topic but how did you make this mockup? Been looking for vector graphics to do some mockups of KDE apps.
Also would it make sense to show the classic menu button if this is available?
The icons come from breeze-icons (of course).
The widgets are entirely made from scratch in Inkscape with the Rectangle, Ellipse, Path->Union and Path->Difference tools.
The shadow is made by putting a black rectangle underneath something and adding blur to the black rectangle.
The text is made with Inkscape's Text tool.
To get the right sizes and proportions, I used KRuler on real Plasma widgets and KWin decorations. I also took screenshots and dropped them into the SVG. Since everything is measured in pixels, the screenshots are always perfect for getting the right proportions.
As for the Menu Button, I think it does make sense. I know I'd still use it even if I had the HUD. That's partly because of muscle memory and partly because it's sometimes faster to hover to an option with a mouse than to type out the name.