Bug 372417

I encounter the very same problem, fullscreen always jumps to one specific monitor, in my case the first one. It should maximize on the screen the window currently is on...

Version 16.04.3 in my case (KDE 5.26, Qt 5.6.1)

How is this still unconfirmed? Has anybody looked at it?

Still happens in 16.12.3.

At least I found a workaround: When Gwenview window is not maximized on that screen going to fullscreen mode works. It only jumps to the other screen if it is already maximized.
Additionally I am not sure if this is connected to having two screens of different resolutions: First screen always catching window: 1440x900 and second screen 1600x1200 in my case

Sorry, cannot reproduce with Gwenview 16.04.3 / KF 5.28 / Qt 5.6.1 as well as Gwenview 17.11.80 / KF 5.39 / Qt 5.9.2.

Please retest with a current version, and add more details if it still happens:
- window manager
- method to launch Gwenview and on which screen
- display resolutions of the primary and secondary screens

In addition, it would be great if you could test on a new user profile to rule out any non-standard configuration options.

Now I am on Gwenview 17.04.3 / KF 5.37 / Qt 5.7.1 but the problem still persists.
I am using Plasma/kwin-5.10.5 and gwenview is opened via double clicking a file in dolphin on the first screen (resolution 1440x900). This opens Gwenview also on the first screen and fullscreen mode is entered there also. Moving the window to the second screen (1600x1200) directly maximizing it by moving it to the top border and then entering fullscreen mode switches fullscreen to the first screen. If the window is moved but not maximized it works as expected.

Thanks for the update; changing status.

Can no longer reproduce.

gwenview 17.08.3
kwin 5.11.4
plasmashell 5.11.4

Arch Linux.

For me it is still valid as described, even given that I now have newer package versions installed than Daniel:
Gwenview 17.12.3 / KF 5.46.0 / Qt 5.9.4 / kwin 5.12.5 but on Gentoo Linux

@Quincy: Just to rule out any weird configuation issue (e.g. KWin's window rules), could you try to reproduce with a fresh/new user account?

Okay, I can now reproduce after noticing a small detail in your more extensive description in Comment 5:
- I does not matter on which screen you first start Gwenview on.
- The important part is that you have to actively move Gwenview to a different screen while at the same time maximizing it (by dragging it to the top of the screen).
- First moving Gwenview and then maximizing in a second step won't trigger the bug upon activating fullscreen mode.

Building on that insight, I tested on more systems and noted the version of Qt:
- I can reproduce with Qt 5.6.2, Qt 5.9.2, Qt 5.9.3 and Qt 5.9.5 (note in particular that the different versions of Qt 5.9 were on various distros and with both older and newer kernels + graphics stacks).
- I cannot reproduce with Qt 5.10.0 and Qt 5.11.0 (Qt 5.11 was tested with both a very old and a very new base distro).

Therefore I suspect Qt 5.10 fixed the problem.

@Daniel: Please let us know your version of Qt, and possibly retest with the more detailed instructions from above.

@Quincy: Do you have a way to test with a newer Qt?

I was just about to test with the new user, but had to wait for other stuff to get finished before restarting with a different user.
It is kind of weird, that Daniel and my behavior fulfilled this rather complicated trigger of moving and maximizing which you luckily now found (and I can reproduce here also).

Qt >=5.10 is not yet available for my one and only distro (Gentoo) without bigger hassle, so unfortunately I will have to wait...