New Lazarus 3.0 opendialog slooow with Qt5, compared to 2.2.6

[cdbc]

Hi
I've just installed (via fpcupdeluxe) fpc trunk & laz 3.0 fixes, all went well, so far, so good. I've got my old fpc 3.2.2 & laz 2.2.6 both stable still installed in /usr/lib64/.... The new 3.0 is installed in my /home/bc/laz_3/... on PCLinuxOS with Qt5.6.... on 4 core amd 16g ram.
In my current project, when i open a filedialog to choose a file to open: in 2.2.6 it's quick and /not/ cpu-hungry, in 3.0 it's sloooow to open and to return + it peaks the cpu @100% on 1 core, a rough timing shows it to be a bit more than 3 times slower...
I can compile the project in both 2.2.6.& 3.0 side by side, no code-changes.
Is that by design or what could be the reason for that?!?
Regards Benny

[zeljko]

But dialogs problem was fixed before 3.0 went out. Is it x11 or wayland ? What qt5 libs do you use ?
Since 3.0 dialogs are changed to use native dialogs (so eg under KDE you'll get KDE open/save dialogs, under Gnome gtk2/3 dialogs etc)

[cdbc]

Hi
It's a X11 system with Qt-5.6.18 and I have compiled my libQt5pas.so fairly recently... I did notice a slight difference in appearence of the dialogs, but that doesn't matter, the speed does though(and cpu spike).
I'd have thought, going native would be speedier 
Anything I can do about it?
Thanks for replying zeljko
Regards Benny

[zeljko]

That's pretty old Qt5 lib. I can patch dialogs, so by native dialogs are disabled by default for Qt5 < 5.9 (I've tested dialogs with 5.9, 5.12, 5.15 - all LTS, like 5.6 is.) If you want it so, please open an issue about it, and fill all details about OS, window manager and Qt lib version.

[cdbc]

Hi
I came to gathering info and realised, I've stated the wrong Qt version...
I switched the numbers... The correct version is Qt 5.15.6; and you've tested against that...
Here are the gathered info:

HP 15 Notebook PC
System = PCLinuxOS 2024 RR
KDE Plasma Version = 5.27.10
KDE Frameworks Version = 5.114.0
Qt Version = 5.15.6
Window manager = KWin
Kernel Version = 6.5.13-pclos1 (64bit)
Display server: X.org v: 1.21.1.11

Is that good enough?
Now I've got to figure out how to open an issue?!?
edit: Should I maybe compile a new libQt5Pas.so, even though mine is newer than @dbannon's in his github?
Regards Benny

[zeljko]

No, you don't need to rebuild libQt5Pas because of that. Can you write what time is needed to open dialog (eg 3 seconds) ?

[cdbc]

Hi
Just timed it on my phone: 3,38 seconds 
Regards Benny