Hi, after upgrading Debian 12 to 13 and KDE with it, language switching behavior changed. I use 3 languages for input, two of which are the most used ones and the third one I only use occasionally. In the previous KDE version, alt+shift changed between the two most used languages back and forth, ignoring the third one, which was very convenient. When I needed the third language I chose it manually. After the upgrade alt+shift simply cycles among all three languages. Can I change this behaviour? Thanks.
The layout switching behavior had been completely rewritten for Plasna 6.2 and 6.3 due to multiple issue with the old X11 behavior (that was ported as is to Wayland and Plasma 6, originally). And this is still an ongoing work.
Originally - on X11 - which is I believe what you were using on Debian 12, there was a concept of “spare layouts” where you specify how many of your layouts are “main” and the rest are “spare” - i.e. they are skipped when switching layouts using the main layout switching shortcut.
On new Plasma 6 on Wayland, “spare layouts” does not work - you can still configure them, but the new Wayland code just doesn’t do it.
The current recommended way to switch between two layouts, back and forth, is to use the “Switch to last used layout” keyboard shortcut, which is configurable by defaults to META+ALT+L. You can find that configuration in System Settings → Keyboard , then press the Configure Switching button at the bottom of the page. The dialog that opens looks like this:
See this discussion for more information and some context.