[Post-Install] Kubuntu 26.04: My experience after several days of daily use and why I returned to 24.04

[wonder]

I have been testing Kubuntu 26.04 for several days as my daily working environment (multi-monitor setup, Chrome, Thunderbird, suspend-then-hibernate, KDE applications, etc.).
In the end I decided to return to Kubuntu 24.04. None of the issues below are critical on their own, but the accumulation of many small problems made the overall experience less comfortable than 24.04 for me.

Wayland / Session Restore

1. With Wayland, multiple browser windows (non-Firefox browsers) are not properly restored after reboot. Only one instance is reopened.
This did not happen to me on Debian 12 with Wayland (KDE 5), which I used on another machine for about a year. Therefore, I am not sure whether this is a KDE 6 issue or a Wayland + Kubuntu issue.

2. With Wayland, if I leave files open in Kate and reboot the system, those files are not restored when Kate starts again.
3. The previous issue disappears when using X11.
Because of the above, I ended up installing and using X11, even though it is no longer the primary supported session.
Multi-Monitor / Window Placement

4. Multiple windows (browser download dialogs, Thunderbird dialogs, etc.) always open on the secondary monitor even though another monitor is configured as primary.
Even if I move them manually, the next time they appear they open on the secondary monitor again.
Dolphin / KDE Usability

5. PDF previews stored on other internal drives are not displayed.
6. Dolphin Settings always opens with a very small window size, requiring manual resizing in order to see all options comfortably.
7. I use single-click activation for files and folders. Selecting files now feels more difficult because the clickable/selection area is larger than before.

Plasma Widgets
8. This seems to be a KDE 6 issue.
System widgets such as Memory Usage, Total CPU Usage and Individual CPU Core Usage do not reliably keep their configuration after reboot.
Widget ordering and settings may change after restarting the system.
It is not a serious problem, but it affects usability.

Application Launcher
9. I use the "Application Dashboard" launcher.
I cannot manage the power-related favorites (shutdown, suspend, hibernate, etc.). I cannot remove them, reorder them, edit them or add them again from the application menu.
Right-click does nothing for these entries, while all other favorite entries work correctly.

Security / Desktop Integration
10. Immediately after login, KWallet asks to be opened.
11. If updates are available and Discover shows its notification icon, opening Discover allows installation without asking for a password. I am not sure whether this is intended behaviour or a bug.

Power Management
12. Suspend-then-hibernate is working correctly in Kubuntu 26.04 (which is a welcome improvement compared to the early days of 24.04).
However, inactivity timers appear inconsistent.
Example:

* Turn off screen after 10 minutes
* Suspend after 20 minutes

Sometimes I leave the computer for 25–30 minutes and everything is still active. Later, the screen finally turns off and suspension occurs.

I have been unable to identify which activity source is preventing the timers from triggering at the configured times. I do not observe this behaviour in 24.04.

Thunderbird / Wayland

13. In 2026, a common desktop workflow such as minimizing Thunderbird to the system tray is still not available under Wayland.
Under X11 this works correctly with Birdtray.
Wayland is supposed to be the future, but some long-standing desktop workflows are still not possible.
https://www.phoronix.com/news/KDE-Plasma-Wayland-Ex-X11

Positive Notes
Not everything was negative.
One pleasant surprise was that hd-idle appears to work correctly out of the box in Kubuntu 26.04. I no longer needed to install or configure it manually.
Overall, I did not encounter any critical failures, crashes or data loss.

However, the accumulation of many small issues made Kubuntu 26.04 less comfortable for my daily workflow than Kubuntu 24.04.
For now, I have decided to remain on 24.04 and revisit 26.04 at a later point.

[boospy33]

First of all, thank you very much for your report. Here are my comments on the things I'm familiar with:

1. With Wayland, multiple browser windows (non-Firefox browsers) are not properly restored after reboot. Only one instance is reopened.
This did not happen to me on Debian 12 with Wayland (KDE 5), which I used on another machine for about a year. Therefore, I am not sure whether this is a KDE 6 issue or a Wayland + Kubuntu issue.

Firefox is the only browser that does this correctly. None of the Chrome-based browsers can do this yet. Wayland integration isn't finished yet. I solved this by launching the Brave browser with the following option: "--ozone-platform=x11 %U". The only downside is that there's no HDR in the browser.

4. Multiple windows (browser download dialogs, Thunderbird dialogs, etc.) always open on the secondary monitor even though another monitor is configured as primary.
Even if I move them manually, the next time they appear they open on the secondary monitor again. 6. Dolphin Settings always opens with a very small window size, requiring manual resizing in order to see all options comfortably.

My resolution is 5120x1440. And yes, that was annoying at first, too. I solved it by configuring the window types and classes with specific positions and sizes. It works very well, but it’s not something you can expect a regular user to do.

5. PDF previews stored on other internal drives are not displayed.

Works here normal.

System widgets such as Memory Usage, Total CPU Usage and Individual CPU Core Usage do not reliably keep their configuration after reboot.
Widget ordering and settings may change after restarting the system.
It is not a serious problem, but it affects usability.

I can confirm that, too. It was incredibly annoying. I finally figured it out when I switched the setting to “Horizontal Bars.” The configuration is saved correctly now, too.

11. If updates are available and Discover shows its notification icon, opening Discover allows installation without asking for a password. I am not sure whether this is intended behaviour or a bug.

I noticed that too. Sometimes it asks for a password, and sometimes it doesn't. I figured it's because sudo is managed centrally via AD/Kerberos here, and certain operations are allowed to be performed without password authentication. But maybe not...

Security / Desktop Integration
10. Immediately after login, KWallet asks to be opened.

Hmm... maybe you changed your password? Or enabled or disabled auto-login?

---

Since I also use it for my daily work, the workstation obviously has to function properly. I stay with 26.04. It has more advantages for me personally. HDR on the desktop and in some games is really pretty cool. And after investing quite a bit of time in getting things right and also submitting a bug report, I hope that the first bug fix update (26.04.1) will resolve some of the issues.

[wonder]

Thank you for taking the time to reply and share your experience.

Firefox is the only browser that does this correctly. None of the Chrome-based browsers can do this yet. Wayland integration isn't finished yet. I solved this by launching the Brave browser with the following option: "--ozone-platform=x11 %U".

This is what confuses me the most.

I used Debian 12 with KDE 5 and Wayland on another machine for about a year, using Chrome-based browsers, and I never experienced this behaviour. Multiple browser windows were restored correctly after reboot.

That's why I'm still unsure whether this is a Chromium limitation, a KDE 6 issue, a Wayland issue, or something specific to the Kubuntu 26.04 stack.

As for launching Brave with "--ozone-platform=x11", I completely understand the workaround, but to me it feels more like avoiding the problem than solving it. If X11 is eventually going away, long-term solutions will have to work natively under Wayland.

My resolution is 5120x1440. And yes, that was annoying at first, too. I solved it by configuring the window types and classes with specific positions and sizes.

I agree that window rules can help in some cases, but many of the windows I mentioned are dynamically generated (browser downloads, Thunderbird save dialogs, etc.), so maintaining rules for all of them quickly becomes impractical.

I can confirm that, too. It was incredibly annoying. I finally figured it out when I switched the setting to “Horizontal Bars.”

Thank you for confirming the Plasma widget issue. Knowing that another user can reproduce it is actually very useful.

I noticed that too. Sometimes it asks for a password, and sometimes it doesn't.

That's interesting.

My system is a standalone home installation without AD, Kerberos or centralized authentication, so your explanation probably does not apply in my case. That is one of the reasons why the behaviour caught my attention.

Hmm... maybe you changed your password? Or enabled or disabled auto-login?

No password changes, no autologin changes and no workflow changes compared to Kubuntu 24.04.

I have also used Debian and openSUSE with KDE in the past and I do not remember KWallet being presented immediately after login before opening any application.

Since I also use it for my daily work, the workstation obviously has to function properly. I stay with 26.04.

I completely understand your decision to stay on 26.04.

For me, reliability and predictability in daily use are more important than the new features, so I eventually decided to return to 24.04.

The issues I encountered were not critical, but there were enough of them to affect my daily workflow.

For now, 24.04 remains the better choice for my use case, and I expect to stay with it for the foreseeable future.