I am on Arch linux, with all the upgrades as of this minute :
kernel: 5.1.7
video driver: nvidia: 430.14
Qt: 5.12.3

I have tested this bug on both the installed Krita (4.2.1) and Krita Plus nightly (krita-4.2.1-468f9b4-x86_64.appimage) .

I have bound the popup color selector to key 'W'. I press W, popup appears, I pick the color. Everything is fine upto this point. But now there are two ways I can close the popup and go back to the drawing canvas :

1. I press W again, the popup closes and everything works fine.
2. I move the mouse outside the popup. The popup closes but now no keyboard shortcut works.

In case#2 above, I can draw fine use mouse/tablet, and can click on menus etc, but keyboard shortcuts stop working entirely. All shortcuts, not just color selector popup. But it gets restored if I alt-tab to other window and come back, or if there is a floating docker and I activate it and then come back to canvas.

To investigate, I downloaded the krita's source code of the nightly plus and installed a native event filter via qApp->installNativeEventFilter. In there, I added the following code (showing only the relevant parts) :

Code: Select all

        case XCB_KEY_PRESS: {
          qDebug() << "xcb key pressed...";
        }
        break;
        case XCB_FOCUS_IN: {
          auto e = reinterpret_cast<xcb_focus_in_event_t*>(event);
          qDebug() << "xcb focus in, seq:" << e->sequence << ", window:" << e->event ;
        }
        break;
        case XCB_FOCUS_OUT: {
          auto e = reinterpret_cast<xcb_focus_in_event_t*>(event);
          qDebug() << "xcb focus out, seq:" << e->sequence << ", window:" << e->event ;
        }
        break;


So I was just inspecting the keypress events, and focus in/out events from xcb. And I ran both the above cases, exiting popup by pressing W again, and then exiting popup by just moving the mouse outside.

When entering with W keypress and then exiting with W keypress, following was the output from my debug code :

xcb key pressed... // <-- I pressed W to open popup
xcb focus out, seq: 4323 , window: 62914587 // <-- Main window loses focus
xcb focus in, seq: 4323 , window: 62915105 // <-- Popup window gains focus
xcb key pressed... // <-- I pressed W to close popup
xcb focus out, seq: 4373 , window: 62915105 // <-- Popup window loses focus
xcb focus out, seq: 4374 , window: 62914587 // <-- Main window loses focus
xcb focus in, seq: 4395 , window: 62914587 // <-- Main window gains focus

You can see, in the end, the main window ends up gaining focus, so this works fine. But now the output if I exit popup by just moving my mouse outside :

xcb key pressed... // <-- I pressed W to open popup
xcb focus out, seq: 4445 , window: 62914587 // <-- Main window loses focus
xcb focus in, seq: 4445 , window: 62915105 // <-- Popup window gains focus
xcb focus out, seq: 4500 , window: 62915105 // <-- Popup window loses focus
xcb focus in, seq: 4500 , window: 62914587 // <-- Main window gains focus
xcb focus out, seq: 4505 , window: 62914587 // <-- Main window loses focus

There is the problem, the main window ends up losing keyboard focus. Now no "xcb key pressed..." happens no matter whatever key I press. If I alt-tab out and then in, or give focus to a floating docker and then go back, then it fixes itself.

At first I thought it would be something like https://bugs.kde.org/show_bug.cgi?id=407978, which is also Arch specific, but in that report testers report that the appimage is fine.

If I test this on my KDE Neon system, with Qt 5.12.0, I don't have any problems, but I also don't have any problems with the 4.2.1 appimage on this system, which has Qt 5.12.3.

Yeah I suspected that this issue is very specific to certain setups, cuz it was there even in 4.2.0 and if it was widespread, it would've been noticed by now. I use Xfce desktop environment, maybe it has to do something with it, not sure though. Going to dig more into this.

Yeah, it was xfwm, xfce's window manager. Installed cinnamon desktop environment and its working fine now.

Ha! Okay -- maybe it would make sense to report a bug to the xfce people?

boudewijn wrote:Ha! Okay -- maybe it would make sense to report a bug to the xfce people?

The version which was installed by system package manager is quite a bit behind, and I dont understand how they version it, probably the 4.X are stable if X is even and unstable if X is odd. The installed one I have is 4.12, whereas 4.13 branches are available there. This is why I didnt immediately filed a report because I cannot compile and test their latest versions. I will see if there is any mention of any keyboard focus related bugs in their changelogs or anywhere, if not then maybe drop them a message first before opening an issue on their bug tracker.

Cool, thanks for the update