Thanks Leonard for reporting and Nate for forwarding.

Leonard, I'm sorry for inconvenience, this is a known problem I currently have in mind, I hoped I could fix it before somebody faced it so I wouldn't have to report the bug, but is didn't happened :)

The thing is variants of the first layout currently do not work.
So as a workaround I could suggest please don't place your Neo layout to the first position. The Layout Settings have Move Up/Down buttons to change layout order. On the first position, place something that doesn't need variants.

Please report if the workaround works for you.
I'm sorry again and hope it doesn't break your workflow much.
The fix should be soon.

Thank you Andrey for your work on the Plasma Wayland code and for pointing out the workaround. The workaround works almost. The only major issue I face now is that the right Alt key no longer works for activating layer 4 of the layout (cf https://neo-layout.org/ "Ebene 4" in the picture in the upper right corner). Pressing the Right Alt key does not perform any action.

For example, Pressing "Right-Alt + D" should result in "Arrow down", but with your workaround results in "a" (which is the expected result of pressing "D" but not for "Right-Alt + D").

A second minor issue I find is that switching keyboard layouts via the shortcut ("Right-Ctrl+Right-Shift" in my case) does not work reliably anymore after moving neo layout to second position.

Specifically, I can activate the neo2 layout via the shortcut fine (Pressing "Right-Ctrl+Right-Shift" switches from US layout to neo2), but pressing the shortcut again does not switch back to US layout.

Leonard, this is probably because the shortcuts of these layouts do not match.
I wonder if you had similar problems with the same layouts but in different order?

So if it worked for you earlier, maybe it was on X11?
It works differently there, see bug 375518.

We could check it right now:
add 3 layouts in different order, and watch how it behaves on the shortcuts:
E.g.: US, US, Neo -> US, Neo, US

So probably we have 2 different issues here, the first one with the variants of the first layout which is the regression indeed, and the second is bug 375518 which is by design and was always there, and only might change in the future.

Let's track the regression here.

> Leonard, this is probably because the shortcuts of these layouts do not match.
> I wonder if you had similar problems with the same layouts but in different order?

The problem does not occur when using Default variant for German or placing the German Neo variant on position 1 and US on 2.

> So if it worked for you earlier, maybe it was on X11?

No, I was using Wayland with Plasma 5.20 and I haven't noticed this problem there. In fact the Right-Shift and Right-Ctrl key used as shortcut by me do not differ between the US and Neo. Thus I don't think it's related to 375518.

If you like, I can reinstall kwin 5.20 and double check that the shortcut works fine there.

> We could check it right now:
> add 3 layouts in different order, and watch how it behaves on the shortcuts:
> E.g.: US, US, Neo -> US, Neo, US

With 4 layouts:
English US, English UK, German Neo, German Default 
I can switch from US to UK to Neo, but then get stuck.

I also notice that switching from US to UK, the overlay notifying me about the new layout shows up immediately. For UK to Neo, the overlay does not show up until I switch the application in focus (eg to my browser where I am writing the bug report now)

In Plasma 5.20, if I use Neo as 1st layout and US as 2nd layout, I can switch between them via "Right-Ctrl + Right-Shift" without getting stuck. But once placing Neo as layout 2 and US as layout 1, switching will get stuck once selecting Neo.

Further I notice that the problem with "Alt key can no longer activate layer 4 (Ebene 4)" is also present on Plasma 5.20 if Neo is selected as 2nd layout. However, Alt key works correctly as long as Neo is selected as 1st layout.

Thus I think the only regression here is "variants of the first layout" support. The others are separate bugs related to difference in handling of 1st and n-th layout. Are these known issues?

(In reply to Leonard Lausen from comment #7)
> In Plasma 5.20, if I use Neo as 1st layout and US as 2nd layout, I can
> switch between them via "Right-Ctrl + Right-Shift" without getting stuck.
> But once placing Neo as layout 2 and US as layout 1, switching will get
> stuck once selecting Neo.
Thanks for testing. Actually I can't explain right now why the order of layouts matters for the shortcut functionality.
It would be good if you could check on X11 also.

> Thus I think the only regression here is "variants of the first layout"
> support. The others are separate bugs related to difference in handling of
> 1st and n-th layout. Are these known issues?
Bug 375518 is the only known to me (it has duplicate).
For any other issues you faced here, please open a separate reports and add me to CC. It might be you've found something new.
Thanks.

Oh, the other workaround I forgot to mention:
just add some variants to both layouts.

> Thanks for testing. Actually I can't explain right now why the order of layouts matters for the shortcut functionality.
> It would be good if you could check on X11 also.

I confirmed that also Plasma 5.20 X11 session, if I use Neo as 1st layout and US as 2nd layout, I can switch between them via "Right-Ctrl + Right-Shift" without getting stuck. But once placing Neo as layout 2 and US as layout 1, switching will get stuck once selecting Neo.

Reported as https://bugs.kde.org/show_bug.cgi?id=432436

> Oh, the other workaround I forgot to mention:
> just add some variants to both layouts.

I compiled 5.20.90 again and Neo variant does work fine now even when on position 1. I assume this is because I manually selected "Default" variant for US English while I was still on 5.20 (ie. both layouts now have a variant configured)

I'll not touch the setting for as not to risk any problems :) Please let me know once you have a patch that fixes the regression and I'm happy to do further testing.

A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/340

Git commit 5cbac50fdb71a17ae60a6f9433541f6e8675eee2 by Andrey Butirsky.
Committed on 08/02/2021 at 15:31.
Pushed by butirsky into branch 'master'.

fix: the first keyboard layout can't have variants

We need trailing comma in case of multiple layouts but only one variant,
see https://github.com/xkbcommon/libxkbcommon/issues/208

M  +3    -1    kcms/keyboard/keyboard_config.cpp

https://invent.kde.org/plasma/plasma-desktop/commit/5cbac50fdb71a17ae60a6f9433541f6e8675eee2

Git commit b9eae656c7b4b16d2d0bb638a76a0197a74a1b8f by Andrey Butirsky.
Committed on 08/02/2021 at 15:33.
Pushed by butirsky into branch 'Plasma/5.21'.

fix: the first keyboard layout can't have variants

We need trailing comma in case of multiple layouts but only one variant,
see https://github.com/xkbcommon/libxkbcommon/issues/208


(cherry picked from commit 5cbac50fdb71a17ae60a6f9433541f6e8675eee2)

M  +3    -1    kcms/keyboard/keyboard_config.cpp

https://invent.kde.org/plasma/plasma-desktop/commit/b9eae656c7b4b16d2d0bb638a76a0197a74a1b8f