SUMMARY

As a curious person, I saw the option to hide the toolbars in Konsole and I thought: "Wait... There's only one toolbar! I wonder what's the difference between the Main Toolbar and a Session Toolbar...". Turns out that if you have the hamburger menu (which is the default now), and you hide the Session Toolbar, the hamburger menu gets hidden as well, and there's no way of finding the option to bring the Session Toolbar back unless you also happen to know the shortcut to bring the menu bar back (CTRL+SHIFT+M).

There are a few possible solutions, but they all bring one drawback or another:

1. Make hiding the toolbar still keep the hamburger menu there. Drawback: Effectively you won't hide the toolbar because it will still need to be there to accommodate the hamburger menu. To completely hide it, you'll also need to enable the menu bar to hide the hamburger menu.

2. Do the same as suggestion 1 but show the menu bar automatically when you hide the toolbar. Pros: Hiding the toolbar won't be a two step process anymore. Drawbacks: This option would overlap with the option to "Show Menubar". E.g:

1. Hide the toolbar (which would show the menu bar)
2. Uncheck "Show Menubar" to hide it as well

You'll get an empty UI, bringing back the same problem of "how do I bring things back to normal?". An empty UI is only useful when running scripts that call Konsole, so disallowing that in normal usage would be fine (should probably be brought back for scripts only with a --hideui command line option). If this suggestion is chosen, it would be wise to change the name from "Show Menubar" to "Switch to Hamburger Menu".

3. Disallow hiding the toolbar in the first place (this will make Konsole inconsistent with other applications, like Dolphin, but would work in principle).

STEPS TO REPRODUCE
1. Go to Hamburger Menu > Settings > Toolbars shown
2. Deselect "Session Toolbar"

OBSERVED RESULT
Hamburger menu is gone and there's no menu bar to replace it. That means you can't also re-enable the toolbar unless you know the shortcut to bring the menu bar.

EXPECTED RESULT
The Hamburger Menu should always be visible when no menu bar is available, even if the user wants to hide the toolbar.

SOFTWARE/OS VERSIONS
Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.27.80
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8
Kernel Version: 5.19.0-32-generic (64-bit)
Graphics Platform: Wayland
Processors: 6 × Intel® Core™ i5-9400F CPU @ 2.90GHz
Memory: 15,6 GiB of RAM
Graphics Processor: AMD Radeon RX 570 Series