Cannot remove TShellListView from form

[Diverod]

   I have a form on which I placed a TShellListView but decided to go with TShellTreeView instead. Unfortunately I didn't try to remove the ListView until much later.
   When I try to delete the TShellListView Lazarus displays the Not Responding message and all I can do is Force Quit.
   Being that my knowledge is limited, was wondering if someone might have another way of removing a control from a form other than selecting the Delete option in the drop-down menu?
   This does not effect the function of my app and Lazarus restarts fine. I can remove the visibility but would like to remove it.
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Lazarus
Version: 3.6
Date: 2024-10-02
FPC Version: 3.2.2
Revision: Unknown
x86_94-linux-gtk2
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Ubuntu 24.04.1 LTS
AMD A12-9720P RADEON R7, 12 COMPUTE CORES 4C+8G × 4
Lenovo ideapad 320-15ABR
GNOME Version: 46
Windowing System: Wayland
Kernel Version: Linux 6.8.0-48-generic
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   Also, I can make a test form with just a button and TShellTreeView. I cannot remove it from this either.

Any help is appreciated.

[Bart]

That should not happen.

In the mean time:

• close Lazarus
• open the .lfm in a text editor
• find the declaration of TShellListView and remove it
• open associated the unit (*.pas;*.pp) in the text editor and also remove the TShellListView from the form definition (TForm1 = class(TForm) etc..)

If you can reliably reproduce the issue with Lazarus 4.0RC1 (or Lazarus main) then please file a bugreport!


Bart

[VisualLab]

There's probably something wrong with the TShellListView destructor. And it could be some internal object that TShellListView creates (and deletes), maybe related to system resources.

[Diverod]

That should not happen.

In the mean time:

• close Lazarus
• open the .lfm in a text editor
• find the declaration of TShellListView and remove it
• open associated the unit (*.pas;*.pp) in the text editor and also remove the TShellListView from the form definition (TForm1 = class(TForm) etc..)

If you can reliably reproduce the issue with Lazarus 4.0RC1 (or Lazarus main) then please file a bugreport!


Bart

Good instructions, worked great!
Thank you!

[wp]

Using Laz/main and FPC3.2.2, I can reproduce the issue on Kubuntu 24.04.1/gkt2 (here also with Laz 3.4) and on Manjaro Plasma 22.05/gtk2 (here also with Laz 3.0).

Simply dropping a TShellListView on an empty form of a new default project is enough to show the issue. Sometimes the listview does not appear at this moment, sometimes it appears a few seconds later. The IDE does not react on deleting the control, becomes inresponsive and later reports a "does not respond error".

There is no issue on Windows and qt5/qt6 (verified on Manjaro Plasma 22.5).

I filed a bug report: https://gitlab.com/freepascal.org/lazarus/lazarus/-/issues/41238

[Bart]

Do we know of any Lazarus version where this worked correctly?
We need a version wehre this worked OK, so we can bisect the guilty revisison.
(I don't see any obvious candidates in the history of TSHellListView.)

I could reproduce the issue in a stand-alone program with just a TShellListView and a TButton.
In the button's onclick I free the TShellListView --> application freezes.
(All this on Linux x86_64, GTK2. No crash wth QT.)

If you hide the TShellListView before freeing it, the app remains responsive, but you get a crash on closing the app, and you still have to kill it.

I can't figure out what is so special about TShellListView that this happens, when it does not happen with a TListView.

Bart

[VisualLab]

I can't figure out what is so special about TShellListView that this happens, when it does not happen with a TListView.

Apparently it references some GNOME, Gtk, or something related resources.

[Bart]

wp found the quilty revision, now just figure out what's wrong with it (proabbly in the WS registration code somewhere).

Bart

[Bart]

Fixed in Lazarus main in commit 9b59add4 and merged to fixes branch.

Bart