SUMMARY
The layout switcher that lets you switch between Logging, Editing, Audio, Effects and Color resides in the top right corner in the menu bar. But because I use a global menu in Plasma, the menu bar is not shown inside the kdenlive window, thus the layout indicator is nowhere to be found.

STEPS TO REPRODUCE
1. Add a global menu widget to your Panel in KDE Plasma
2. Open Kdenlive

OBSERVED RESULT
The layout switcher is gone, as it is not shown in the global menu.

EXPECTED RESULT
The layout switcher is still shown somewhere, even though there's no menu bar inside the kdenlive window.

ADDITIONAL INFORMATION
I know that you can switch between layouts using keyboard shortcuts or the "View" menu, but that is not as convenient and most importantly there's no visual indication what layout you are currently in.