Breeze has design that groups the toolbar and the titlebar, however, some this makes the tab panel to look weird in some applications:
Dolphin has a little spacement, KSysGuard doesn't and Konsole tab bar blends with the outline that groups the titlebar and the toolbar. Plus, the tab panel seems to be too squeezed.
Proposal:
- Every application that have tabs would need to be updated;
- The titlebar and toolbar could have the same background as the rest of the window (as it is in Arc KDE):