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IDProjectCategoryView StatusLast Update
0035057LazarusWidgetsetpublic2020-04-15 18:59
ReporterTomáš Assigned ToZeljan Rikalo  
Status resolvedResolutionno change required 
Product Version2.0 
Summary0035057: Shell dialogs in QT5 widgetset causes AV after application is closed
DescriptionEvery dialog window that uses directory or file lists and is executed, causes AV after application is closed. I tried font dialog and it does not causes it. GTK2 works fine.

It doesn't matter if the dialog is placed on a form or created and freed locally, AC shows up always after app is closed.

I have QT v5.9.4 + libQt5Pas1 v2.0.0

I didn't have this issue with Lazarus 1.8.2 (QT v5.9.4 + libQt4Pas5 v2.5).

I think it's an issue with bindings to QT libraries.
Steps To Reproduce1.) Execute any shell dialog
2.) Close the dialog, no need to select a file or directory
3.) Close the application
TagsNo tags attached.
Fixed in Revision
Attached Files


related to 0036019 resolvedZeljan Rikalo Qt5 programs on exit terminated with Segmentation fault 


Zeljan Rikalo

2019-02-10 18:11

developer   ~0114015

Please write what desktop environment are you using (kde,gnome etc) and what theme is used by Qt5.

Zeljan Rikalo

2019-02-10 18:14

developer   ~0114016

I cannot reproduce it here, Fedora 25 64bit.


2019-02-10 22:05

reporter   ~0114021

I found out it happens only in KDE (Plasma 5). GNOME or TWM have no issues. I guess this bug is outside of Lazarus / FPC...

Zeljan Rikalo

2019-02-11 08:31

developer   ~0114024

Do you use native dialogs or qt internal dialogs ?


2019-02-11 13:51

reporter   ~0114032

If native means from palette "Dialogs" then yes.

Zeljan Rikalo

2019-02-11 16:15

developer   ~0114039

No, native means that you're using qt5lcl with -dQT_NATIVE_DIALOGS compiled in, so on KDE qt5 lazarus app opens KDE open dialog, on win32 it opens native win32 dialog etc....


2019-02-11 18:21

reporter   ~0114041

-dQT_NATIVE_DIALOGS makes no difference (recompiled Lazarus or app). In GNOME was used different dialog, but in KDE the same one.

Should be "qt5lcl" an unit? I didn't find anything like it.

Zeljan Rikalo

2019-02-12 17:49

developer   ~0114055

No, -dQT_NATIVE_DIALOGS in lazarus build options is enough. If it's enabled you'll see KDE native open dialog, under Gnome you'll see Gtk2/3 open dialog.


2019-06-12 22:31

reporter   ~0116704

Tried once again in Lazarus 2.0.2 and the bug is still preserved. Even dialogs in Lazarus itself ("Open", "Save as").

Zeljan Rikalo

2019-06-13 14:51

developer   ~0116708

I cannot reproduce your problem - Fedora 25, Fedora 29, LinuxMint 19 all 64bit with various Qt5 versions (5.6..5.12)

Zeljan Rikalo

2019-10-07 19:40

developer   ~0118397

Last edited: 2019-10-07 19:42

View 2 revisions

This is KDE bug in kf5-kio-core-libs-5.59 (I'm using it on Fedora 29). Currently bug is fixed in Fedora testing repo (kio core is patched).
Just try next in terminal:
XDG_CURRENT_DESKTOP=Plasma ./yourapplication

if XDG_CURRENT_DEKSTOP=KDE then you got crash, anything else does not crash.

Edit: it should be XDG_SESSION_DESKTOP

Zeljan Rikalo

2020-04-15 18:59

developer   ~0122160

1. It's about fpc-3.0.4, problem with alignment is fixed in r38400, so fpc-3.2.0beta contains fix, fpc trunk also.
2. It's about KioCore bug which is fixed few months ago.

Please close.

Issue History

Date Modified Username Field Change
2019-02-10 12:30 Tomáš New Issue
2019-02-10 14:29 Zeljan Rikalo Assigned To => Zeljan Rikalo
2019-02-10 14:29 Zeljan Rikalo Status new => assigned
2019-02-10 18:11 Zeljan Rikalo LazTarget => -
2019-02-10 18:11 Zeljan Rikalo Note Added: 0114015
2019-02-10 18:11 Zeljan Rikalo Status assigned => feedback
2019-02-10 18:14 Zeljan Rikalo Note Added: 0114016
2019-02-10 22:05 Tomáš Note Added: 0114021
2019-02-10 22:05 Tomáš Status feedback => assigned
2019-02-11 08:31 Zeljan Rikalo Note Added: 0114024
2019-02-11 13:51 Tomáš Note Added: 0114032
2019-02-11 16:15 Zeljan Rikalo Note Added: 0114039
2019-02-11 18:21 Tomáš Note Added: 0114041
2019-02-12 17:49 Zeljan Rikalo Note Added: 0114055
2019-06-12 22:31 Tomáš Note Added: 0116704
2019-06-13 14:51 Zeljan Rikalo Note Added: 0116708
2019-08-28 10:12 Zeljan Rikalo Relationship added related to 0036019
2019-10-07 19:40 Zeljan Rikalo Status assigned => confirmed
2019-10-07 19:40 Zeljan Rikalo Note Added: 0118397
2019-10-07 19:42 Zeljan Rikalo Note Edited: 0118397 View Revisions
2020-04-15 18:59 Zeljan Rikalo Status confirmed => resolved
2020-04-15 18:59 Zeljan Rikalo Resolution open => no change required
2020-04-15 18:59 Zeljan Rikalo Widgetset QT5 => QT5
2020-04-15 18:59 Zeljan Rikalo Note Added: 0122160