From kde-panel-devel  Wed Aug 31 10:56:33 2016
From: Alex Maystrenko via KDE Bugzilla <bugzilla_noreply () kde ! org>
Date: Wed, 31 Aug 2016 10:56:33 +0000
To: kde-panel-devel
Subject: [Breeze] [Bug 368048] New: Very strange QLineEdit inside QMenu glitch under extreemly specific condi
Message-Id: <bug-368048-165951 () http ! bugs ! kde ! org/>
X-MARC-Message: https://marc.info/?l=kde-panel-devel&m=147264100705455

https://bugs.kde.org/show_bug.cgi?id=368048

            Bug ID: 368048
           Summary: Very strange QLineEdit inside QMenu glitch under
                    extreemly specific conditions
           Product: Breeze
           Version: 5.7.3
          Platform: Archlinux Packages
               URL: https://github.com/technic/qt5-bug/blob/master/bug.png
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: general
          Assignee: plasma-devel@kde.org
          Reporter: alexeytech@gmail.com

This strange thing initially happened in LXQt project, you may see discussion
here https://github.com/lxde/lxqt/issues/1109

However, I've figured out that this looks like Qt, Breeze or Xorg bug. I am
posting it here, because in my case it is reproducible only with breeze and
oxygen theme, but not with fusion. Maybe, additional factors like video drivers
are also important.

I created an example, that illustrates the bug:

There is a QWidgetAction based on QLineEdit, that is added to QMenu. There is a
function, that deletes old QMenu instance and creates a new one, but
QWidgetAction is moved to new parent with removeAction/addAction functions.
Everything works fine so far.

But next two lines of code added simultaneously, break widget drawing. We set
background for the root QMenu, and added a child QMenu:
mMenu->setStyleSheet("QMenu { background: rgba(240, 0, 0, 100%); }");
QMenu *submenu = new QMenu(mMenu);

Hmm...?)))



Reproducible: Always

Steps to Reproduce:
1. go to https://github.com/technic/qt5-bug and build the project
2. run it and wait for 3sec (glitch creation is managed by timers)

Actual Results:  
A transparent space instead of QLineEdit (see screenshot)

Expected Results:  
QLineEdit popup:
https://github.com/technic/qt5-bug/blob/master/ok.png

Only breeze and oxygen themes are affected. Fusion theme works fine.

Qt 5.7.0, radeon opensource driver.

-- 
You are receiving this mail because:
You are the assignee for the bug.