This issue report is in regards to: (In reply to Nate Graham from https://bugs.kde.org/show_bug.cgi?id=494736#c8) > Yes, the panel itself has some inner margins that widgets can't exceed. So > I'm afraid it's not going to be possible to make the tech literally touch > the edges of the panel like your mockup indicates. Can this be fixed?
It's not a bug, it's a design feature — or rather a design decision of the Plasma theme. The Plasma theme specifies a default internal padding for all panels, and panels then respect that.