Bug 476816

Summary:	FormLayout flashes or flickers when initially loading, as if it starts in narrow mode and then immediately changes into wide mode
Product:	[Frameworks and Libraries] frameworks-kirigami	Reporter:	Vishwas Parpattegar <vishwasparpattegar>
Component:	general	Assignee:	kdelibs bugs <kdelibs-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	minor	CC:	benjamindedieu, bugseforuns, fernandommuniz, jpetso, kde, kde, natalie_clarius, nate, notmart, vishwasparpattegar
Priority:	NOR	Keywords:	qt6
Version First Reported In:	Master
Target Milestone:	Not decided
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Vishwas Parpattegar 2023-11-11 03:07:20 UTC

SUMMARY
***
Energy Saving menu in system settings flashes and moves right when switching between power profiles using the new menu.
***


STEPS TO REPRODUCE
1.  Open System Settings
2. Navigate to Energy Saving Menu
3.  Switch between "On AC Power" / "On Battery" / "On Low Battery"

OBSERVED RESULT
the options below the header bar flash and move to the right when switching between options

EXPECTED RESULT
the options should switch between each other without flashing

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE Neon Unstable Edition
KDE Plasma Version: 5.81.0
KDE Frameworks Version: 5.245
Qt Version: 6.6.0

Comment 1 Nate Graham 2023-11-15 19:28:58 UTC

Can reproduce.

Comment 2 ratijas 2023-11-16 12:21:54 UTC

That's because layout (specifically, FormLayout) is based on timers instead of polish lifecycle callbacks. I'm afraid it can't be entirely fixed without rewriting it to the native code, because we don't get enough level of control in QML code; an alternative to that would be to recalculate the whole layout of every geometry or children change of anything, which would be (1) quite expensive computationally-wise, (2) prone to binding loops and polish loops.

Comment 3 Nate Graham 2023-11-16 20:35:10 UTC

Right, I can see it when I switch between applet config pages for the Task Manager. The FormLayout flickers in the same way as it loads.

Comment 4 Jakob Petsovits 2024-01-07 02:49:10 UTC

Flicker in the Energy Saving module was fixed via https://invent.kde.org/plasma/powerdevil/-/merge_requests/302 by reusing one form for all power state profiles. Nate's reproduction in the "Configure Task Manager" dialog (and likely in several other spots) can still be observed.

Comment 5 Nate Graham 2025-03-19 22:32:31 UTC

*** Bug 500572 has been marked as a duplicate of this bug. ***

Comment 6 Nate Graham 2025-03-28 22:52:07 UTC

*** Bug 502100 has been marked as a duplicate of this bug. ***

Comment 7 David Edmundson 2025-03-31 22:23:04 UTC


*** This bug has been marked as a duplicate of bug 410352 ***

Comment 8 Nate Graham 2025-06-24 16:36:32 UTC

*** Bug 505892 has been marked as a duplicate of this bug. ***

Comment 9 Niccolò Venerandi 2025-08-27 18:58:40 UTC

Git commit 7319360c81238a4e766f3c7093d4f607745183da by Niccolò Venerandi.
Committed on 27/08/2025 at 18:58.
Pushed by niccolove into branch 'master'.

Immediately update value for wideImplicitWidth

This solves some initial load flickering in some form layouts,
such as the accessibility subpages.

M  +7    -10   src/layouts/FormLayout.qml

https://invent.kde.org/frameworks/kirigami/-/commit/7319360c81238a4e766f3c7093d4f607745183da