Bug 337491 - KDEPlatformTheme plugin causes text artifacts in Qt 5 application
Summary: KDEPlatformTheme plugin causes text artifacts in Qt 5 application
Status: RESOLVED FIXED
Alias: None
Product: frameworks-kxmlgui
Classification: Frameworks and Libraries
Component: general (show other bugs)
Version: unspecified
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: kdelibs bugs
URL:
Keywords:
: 338421 345023 353150 357418 394010 (view as bug list)
Depends on:
Blocks:
 
Reported: 2014-07-16 11:25 UTC by Kai Koehne
Modified: 2019-01-12 17:39 UTC (History)
35 users (show)

See Also:
Latest Commit:
Version Fixed In:


Attachments
Screenshot showing "Detai&ls" artifact (22.20 KB, image/png)
2014-07-16 11:25 UTC, Kai Koehne
Details
Example of custom QTabWidget titles becoming shortcuts (207.21 KB, image/png)
2016-12-22 11:47 UTC, cmdrkotori
Details

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Description Kai Koehne 2014-07-16 11:25:24 UTC
Created attachment 87756 [details]
Screenshot showing "Detai&ls" artifact

Launching Qt Creator in the just released Plasma 5 causes mysterious text issues: Namely that the "Details" button is in some places displayed as "Detai&ls" (see attached screenshot).

This is apparently caused by the loading of KDEPlatformTheme.so into the process: The artifact doesnt' show up with QT_PLUGIN_PATH set to empty, or when manually removing KDEPlatformTheme.so

Original bug report for Qt Creator:

https://bugreports.qt-project.org/browse/QTCREATORBUG-12680
Comment 1 Kai Koehne 2014-07-16 11:41:02 UTC
It seems KAcceleratorManager is actually to blame. Here's a stack trace where the '&' is injected into the QAbstractButton:


5	QAbstractButton::setText	qabstractbutton.cpp	646	0x7ffff6eaf5ad	
6	QAbstractButton::qt_metacall	moc_qabstractbutton.cpp	241	0x7ffff71c68f9	
7	Utils::DetailsButton::qt_metacall	moc_detailsbutton.cpp	221	0x7ffff770cb9c	
8	QMetaObject::metacall	qmetaobject.cpp	308	0x7ffff56e4f23	
9	QMetaProperty::write	qmetaobject.cpp	2926	0x7ffff56ea773	
10	QObject::setProperty	qobject.cpp	3827	0x7ffff571f285	
11	KAcceleratorManagerPrivate::calculateAccelerators		172	0x7fffe8425e8a	
12	KAcceleratorManagerPrivate::manage		113	0x7fffe84271a3	
13	KAcceleratorManager::manage		435	0x7fffe8427301	
14	KCheckAccelerators::checkAccelerators		258	0x7fffe8be9183	
15	KCheckAccelerators::autoCheckSlot		208	0x7fffe8bea1be	
16	QMetaObject::activate	qobject.cpp	3680	0x7ffff571ea2a	
17	QMetaObject::activate	qobject.cpp	3546	0x7ffff571e238	
18	QTimer::timeout	moc_qtimer.cpp	191	0x7ffff57af783	
19	QTimer::timerEvent	qtimer.cpp	255	0x7ffff572993f	
20	QObject::event	qobject.cpp	1222	0x7ffff5717faa	
...	<More>
Comment 2 Christoph Feck 2014-07-16 16:24:38 UTC
Is there a reason why the button class does not support keyboard accelerators? If yes, how can I detect whether a button class refuses to support them?
Comment 3 Kai Koehne 2014-07-17 12:26:23 UTC
The DetailsButton class is part of Qt Creator, and used only in contexts where shortcuts don't make much sense (Projects Pane). It paints on it's own (ignoring any system styles): http://code.woboq.org/qt5/qt-creator/src/libs/utils/detailsbutton.cpp.html#_ZN5Utils13DetailsButton10paintEventEP11QPaintEvent


I guess this particular issue could be fixed by passing Qt::TextHideMnemonic to QPainter::drawText in DetailsButton::PaintEvent. I don't see, however, how one could force this 'from the outside', and it feels wrong to work around this in Qt Creator.

The root problem is IMO that KDE 'injects' shortcut keys into applications. I'd have expected that it's the applications job to define sensible shortcuts where deemed necessary.
Comment 4 Kai Koehne 2014-07-23 08:33:36 UTC
This btw causes one more regression in Qt Creator: The "Session" submenu in "File" doesn't work.

This submenu contains a list of checkable QActions for available sessions (in a radio button group). If one now selects one menu entry Qt Creator compares the text() of the selected action with the list of available sessions...

This fails if text() returns something different from what we set originally.
Comment 5 David Edmundson 2014-08-13 13:56:04 UTC
A different QStyle with a polish event could cause this too, even a different translation could put in a mnemonic. 

I'll move this to the right component within KDE, but personally I think the majority of the blame is QtCreator.
Comment 6 Christoph Feck 2014-08-21 00:30:40 UTC
*** Bug 338421 has been marked as a duplicate of this bug. ***
Comment 7 Loïc Yhuel 2014-08-21 10:05:09 UTC
(In reply to Christoph Feck from comment #6)
> *** Bug 338421 has been marked as a duplicate of this bug. ***
So KDE assigns an Alt+G accelerator to the "Go Back" button, even if it doesn't show any text.

With KDE4, KCheckAccelerators::initiateIfNeeded was only called for KDE applications (KApplication).
Now with KF5, any Qt application which loads libKF5XmlGui will call KCheckAcceleratorsInitializer::initiateIfNeeded, that's why QtCreator is affected.

A workaround is to add
[Development]
AutoCheckAccelerators=false
to kdeglobals, which prevents KDE from automatically adding accelerators.
Comment 8 Lastique 2015-06-18 20:29:43 UTC
A possibly related issue: https://bugs.kde.org/show_bug.cgi?id=345023
Comment 9 BogDan Vatra 2015-08-18 05:51:17 UTC
(In reply to Loïc Yhuel from comment #7)
> (In reply to Christoph Feck from comment #6)
[..]
> A workaround is to add
> [Development]
> AutoCheckAccelerators=false
> to kdeglobals, which prevents KDE from automatically adding accelerators.

kdeglobals, from ~/.config not from ~/.kde/share/config
Comment 10 Salvo "LtWorf" Tomaselli 2015-12-28 16:35:27 UTC
I can confirm the issue, and this doesn't only affect 1 application, but any Qt application that defines shortcuts with Alt+something.

Please consider disabling this, at least for non-kde applications.

I just came here because I was having severe problems implementing Qt shortcuts, and it was caused by this bug.
Comment 11 Salvo "LtWorf" Tomaselli 2015-12-28 16:38:08 UTC
What I meant is that my application is creating shortcuts such as "Alt+F" which Kde assigns to a button, so they conflict and the shortcut no longer works.

So basically, shortcuts within Qt applications might not work at all within KDE, depending on which buttons are shown and which shortcuts are created.

This is why I believe it's a rather important issue. The problem is not only about the artifacts.
Comment 12 Chusslove Illich 2016-01-10 22:20:07 UTC
*** Bug 357418 has been marked as a duplicate of this bug. ***
Comment 13 Chusslove Illich 2016-01-10 22:24:22 UTC
This behavior is related to the code in KXmlGui, and not related to any code in KI18n, so reassigning for that reason alone to KXmlGui. Otherwise I have no idea what should be done here.
Comment 14 Kenneth Perry 2016-02-05 21:38:33 UTC
LMMS also triggers this : when built for Qt5, it creates a QMenu containing QActions which contain the recent files loaded. When you press one it uses its text() to load the file - and loading files like /&home/whatever doesn't work.
Comment 15 Richard Heck 2016-06-30 20:10:04 UTC
We have had reports of this same bug in LyX. See http://www.lyx.org/trac/ticket/10261.
Comment 16 cmdrkotori 2016-12-22 11:47:35 UTC
Created attachment 102941 [details]
Example of custom QTabWidget titles becoming shortcuts

I'm also encountering this in my own program (https://github.com/cmdrkotori/mpc-qt). A playlist tab that gets an 'I' ampersanded conflicts with the default Alt-I take screenshot shortcut.  This does not happen on a Windows build.  If there were a way to turn this off at runtime without introducing extra dependencies (e.g. an environment variable), that'd be really good.
Comment 17 Janek Bevendorff 2017-03-16 15:37:52 UTC
Would it be possible to remove this "feature"? It is super annoying. We are also fighting with ugly text artifacts in our application. We also cannot read back any text from the user interface, because whatever text we read from a label or menu entry is probably not what we initially wrote there. This has already cost me a lot of time to hunt down weird bugs where things somehow didn't work on KDE, but on all other platforms.
Comment 18 Alex Maystrenko 2017-06-01 12:10:04 UTC
Hi,
from my point of view, your are taking to much responsibility Dear KDE developers.
The shortcuts are an application own business and intercepting that is bad architecture decision.
Comment 19 matthias sweertvaegher 2017-06-27 18:06:44 UTC
noob question: does KDE do that to make global shortcuts work or is that totally unrelated?
Comment 20 Christoph Feck 2017-06-27 18:52:01 UTC
It is unrelated to global shortcuts. These accelerators are local shortcuts, they are accessed with Alt key while the window is active.
Comment 21 cmdrkotori 2017-07-22 05:36:43 UTC
Here's how I solved it. It's a bit ugly.

.pro file:
LIBS += -ldl

.c++ file:
#include <dlfcn.h>

void Helpers::disableSystemAccel(QWidget *what)
{
    void *d = dlopen("libKF5WidgetsAddons.so", RTLD_LAZY);
    if (!d)
        return;
    typedef void (*DisablerFunc)(QWidget *);
    DisablerFunc setNoAccel;
    setNoAccel = reinterpret_cast<DisablerFunc>(dlsym(d, "_ZN19KAcceleratorManager10setNoAccelEP7QWidget"));
    if (setNoAccel)
        setNoAccel(what);
    dlclose(d);
}

Call this function in your object's constructor.
Comment 22 Salvo "LtWorf" Tomaselli 2017-07-22 08:12:46 UTC
But, my project is in PyQt…
Comment 23 cmdrkotori 2017-07-22 08:32:39 UTC
(In reply to Salvo "LtWorf" Tomaselli from comment #22)
> But, my project is in PyQt…

You should be able to do the same with ctypes.
Comment 24 Leonardo Backes 2017-08-29 20:55:30 UTC
This bug also affects me in the same way as it does to Janek; We made a little keyboard with buttons, where we had to add the same information as text and as another property.
Also, as a GUI developer, if I don't assign a hot key to a given button, it is because it should not have a hot key.

This also causes troubles on Qt Designer, where it eventually adds & to the labels on the .ui file being edited.

cmdrkotori's solution should be available as a user configuration, imho.
Comment 26 Christoph Feck 2017-10-04 13:20:27 UTC
*** Bug 345023 has been marked as a duplicate of this bug. ***
Comment 27 Christoph Feck 2017-10-04 13:20:52 UTC
*** Bug 353150 has been marked as a duplicate of this bug. ***
Comment 28 michael 2017-12-17 05:03:39 UTC
Just confirmed this behavior breaks custom actions in QGit 3.7.
Comment 29 Cristian Adam 2018-05-11 15:35:33 UTC
AutoCheckAccelerators is breaking Falkon too, see: #394010
Comment 30 David Rosca 2018-05-11 15:35:56 UTC
*** Bug 394010 has been marked as a duplicate of this bug. ***
Comment 31 Oleksandr Natalenko 2018-08-09 14:15:12 UTC
It looks like the same applies to Clementine:

https://github.com/clementine-player/Clementine/issues/5931
Comment 32 perrantrevan 2018-09-05 14:36:08 UTC
This bug also affects users of Retroarch's Qt Desktop Menu UI. 

https://github.com/libretro/RetroArch/issues/7112#issuecomment-418535423
Comment 33 perrantrevan 2018-09-05 14:36:38 UTC
This bug also affects users of Retroarch's Qt Desktop Menu UI. 

https://github.com/libretro/RetroArch/issues/7112#issuecomment-418535423
Comment 34 Alexander Wilms 2018-09-05 16:47:36 UTC
FlightGear's Qt launcher is affected as well.
Comment 35 Wren Turkal 2019-01-11 04:31:16 UTC
I would really love for this feature to be removed. I was modifying a window in qtdesigner. It was super frustrating until I figured out how to disable it.
Comment 36 Albert Astals Cid 2019-01-12 17:39:50 UTC
Git commit 02b523bad09aab062355e46771889b0f3709692f by Albert Astals Cid.
Committed on 12/01/2019 at 17:39.
Pushed by aacid into branch 'master'.

Make KCheckAccelerators less invasive for apps that don't directly link to KXmlGui

Summary: BUGS: 337491

Test Plan:
Ran qtcreator and it no longer has the & in Details
Added some debug and checked that okular still gets the code called

Reviewers: anthonyfieroni

Reviewed By: anthonyfieroni

Subscribers: davidedmundson, anthonyfieroni, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D18204

M  +36   -2    src/kcheckaccelerators.cpp

https://commits.kde.org/kxmlgui/02b523bad09aab062355e46771889b0f3709692f