Odd behaviour with Oxygen on Wayland

[Martin Holmes]

Hi there,
Wayland is rapidly becoming the default on Linux, and when we upgrade our lab later this year, the machines will all be on Wayland rather than XOrg, In anticipation of this, we've been running Wayland on various machines to see what transpires. We're noticing a sporadic but persistent problem as follows:
- You're typing in Oxygen in text mode, and you hit a keyboard shortcut such as Control + E to insert a tag.
- The focus switches away from Oxygen to the last app you were using on that desktop, and anything you type after that goes into that app instead of Oxygen.
Has anyone else noticed this? If so, have you found any workarounds?

[xephon]

It seems that gnome and Oxygen use the same shortcut. Have you tried changing the shortcut in either gnome or Oxygen?

[adrian]

Hello,

Unfortunately Java doesn't currently provide proper Wayland desktop support. There is an ongoing project regarding this,
OpenJDK Project Wakefield.

This is the most recent info I can find regarding this project:
https://inside.java/2024/03/24/openjdk-wakefield/

In the meantime, do note that Oxygen does not officially support Wayland, as mentioned on the download page:

The version of Java bundled with Oxygen requires X.org. Wayland is not supported.

I don't recommend switching to Wayland at this time, if you depend on Oxygen and/or Java apps. You may encounter some issues with Wayland that we cannot control.

Regards,
Adrian

[martindholmes]

Wayland is going to be the default on the most common desktops in the very near future, so sticking with X11 isn't really a workable option for Linux users.

[martindholmes]

@xephon, I can't find any sign of a Ctrl + E shortcut in Gnome. Where did you see this?

[martindholmes]

I've just upgraded to Ubuntu 24.04, and this problem is back with a vengeance; it's also happening under X as well as Wayland, so it's not connected to that. These are the symptoms:

1. Work in another application.
2. Alt + Tab to Oxygen. Oxygen receives the focus, and a cursor is apparent in the Oxygen editor.
3. Type or use the keyboard: nothing happens in Oxygen, although sometimes another application receives the keyboard events.
4. Click away from Oxygen and back again, OR move the mouse up to the Oxygen title bar and back again, and Oxygen does receive the focus properly, and typing now works.

This is happening many times a day. I'm using the latest Oxygen with its built-in Java.

[adrian]

Hello,

We've recently tested Oxygen v26.1 on Ubuntu 24 Desktop but did not observe the described issues.
I'd like to point out that from this:

3. Type or use the keyboard: nothing happens in Oxygen, although sometimes another application receives the keyboard events.

if the events get to another application and not Oxygen, it may be a window manager issue (app appears to be selected, but does not actually have keyboard focus, so it does not receive keyboard events). Or in the very least it's an issue between Java and the window manager.

What you can try is to install OpenJDK 17 JRE from the Ubuntu repository (apt install openjdk-17-jre). Do note that OpenJDK 21 or 22 are not supported by Oxygen v26, so we cannot recommend them.
Then rename the "jre" folder from the Oxygen installation folder (e.g. "jre.old") and run Oxygen like this. It will complain about the Java vendor at startup, but as long as the version if supported, it should allow you to continue.
You can check what version of Java is Oxygen using in Help > About, System properties, java.vm.vendor, java.vm.version.

Regards,
Adrian

[martindholmes]

We're now seeing this across more computers, and happening more frequently; we're using the bundled JRE mostly, although I will now test with a separate JRE for a few days. It's quite annoying and also destructive -- you end up typing or pasting in contexts you didn't expect to, or you think you've typed or pasted somewhere but nothing went into the document. I can't find any reports that the problem appears in Eclipse, so I presume it's something specific to Oxygen. I'll report back when I've spent a few days using a different JRE. The problem is that we use OpenJDK 21 as our base Java install, so switching to 17 is going to be tricky.

[adrian]

Hi,

Comparing Oxygen with Eclipse isn't really apples too apples.
Eclipse uses SWT (native UI components), while Oxygen uses Swing (mimics UI components). It's usually the Swing implementation from Java that has issues.
Can you test with a different Java app that uses Swing, (e.g. IntelliJ IDEA or Netbeans)?

The problem is that we use OpenJDK 21 as our base Java install, so switching to 17 is going to be tricky.

For starters, as long as it's not in production, you can test Oxygen 26.1 with OpenJDK 21, at least test for the issue you are encountering. It does run with 21, but you may experience some unforeseen issues.

Regards,
Adrian

[martindholmes]

We've now been able to pin this down a bit and reproduce it 100% reliably:

1. Open Oxygen and at least one other application.
2. Set the focus to Oxygen.
3. Select some text in an XML file and press Control + E to insert a tag; select a tag and hit return to apply it.
4. Try do do anything with the keyboard. The keyboard focus has been switched to the last other application that had the focus before Oxygen.
Pressing Alt + Tab to cycle through applications will eventually bring the focus back to Oxygen.

This is on Ubuntu 24.04, using the JRE packaged with Oxygen. It happens with both Wayland and X. We think it may have something to do with Oxygen showing a dialog box, then that dialog box being dismissed.

[adrian]

Hi,

That seems to indicate a window hierarchy problem (focus should return to the parent window). What window manager are you using?

We've tested this in a Ubuntu Desktop 24 VM with Text Edit as the other app, but cannot reproduce the issue.
Are there any other specifics or particularities of the setup?
Perhaps multiple screens, or a specific graphics card/driver (if on metal)?
Do you have multiple systems/instances with this problem?

Regards,
Adrian

[martindholmes]

This is now happening reliably on at least 13 computers (all real computers, not VMs), running a variety of OSes -- mostly Ubuntu 24.04 with Wayland, but also 22.04 with X, PopOS, and Debian. There's nothing the machines have in common in terms of hardware or graphics cards, except that they almost all have multiple monitors (although I'm pretty sure I've encountered it on a laptop too). The symptom is always that the mouse focus remains in Oxygen, but the keyboard focus is migrated away to another app, usually the last one that had focus before Oxygen.

We're now having to train people to alt-tab away and back again whenever they type and nothing happens. It's really quite frustrating.

Have you really had no other reports of this? It's hard to believe we're the only ones having it.

Cheers,
Martin

[adrian]

Hi,

No, I'm afraid this is the only report we've had about this. So it's rather unusual that the issue is so spread in your environment. I would have expected this to fall under some hardware or software setup peculiarity which causes Java to misbehave...

I guess this may be something that only reproduces with real hardware (probably graphics card). I'll submit a task for our QA team to test this on metal, but it could take a while to set this up. We mostly use VMs for testing.
In the meanwhile, on one of the Ubuntu 24 systems that is affected, could you please send us a problem report from within Oxygen, Help > Report problem?

The problem is that we use OpenJDK 21 as our base Java install, so switching to 17 is going to be tricky.

On another note, have you considered testing this with OpenJDK 21 that the Ubuntu repository has to offer?

... rename the "jre" folder from the Oxygen installation folder (e.g. "jre.old") and run Oxygen like this. It will complain about the Java vendor at startup, but as long as the version if supported, it should allow you to continue.
You can check what version of Java is Oxygen using in Help > About, System properties, java.vm.vendor, java.vm.version.

Regards,
Adrian

[martindholmes]

Hi Adrian,
I'm going to install Oxygen 27.0 today and run with that for a few days to see if the problem goes away; for all we know it's something specific to 26.0 and the JRE that comes with it. If it's still there in 27.0, I'll try the JRE switch and see how that goes. If nothing works, I'll file a report from Oxygen.
Thanks,
Martin

[martindholmes]

I hit the issue within minutes of installing Oxygen 27.0. This time it was triggered by alt+tabbing from Firefox to Oxygen; Oxygen received the mouse focus, but when I started typing, the text went to Firefox. Alt+tabbing back and forth one more time fixed it. This is also a common pattern.
I'm going to stick with this for the rest of the day, and then next week some time I'll try renaming the JRE and letting it run under OpenJDK (currently openjdk 21.0.5 2024-10-15).