[QScintilla] [Eric] [eric6] small glitch with fix and some notes

[Hans-Peter Jansen]

Am Donnerstag, 28. November 2019, 20:12:25 CET schrieb Hans-Peter Jansen:
> Am Donnerstag, 28. November 2019, 19:27:51 CET schrieb Detlev Offenbach:
> 
> Dear @audience, would you test these ill-behaviors and report, please?
> 
> > I have the strong impression, that this is a Qt issue.
> 
> Yeah, smells like that. Unfortunately, without a minimal example, it's
> rather pointless to report such issues (even with code, it's a matter of
> luck to find somebody who cares).
> 
> Will start with a report to openSUSE Factory.

Okay, here's the current state of affairs:

There's a tab view focus issue in eric: when switching tabs with Ctrl-Alt{,-
Shift}-TAB, the focus (cursor) from editor widgets disappear. A click into the 
widget make the cursor reappear.

There's a focus related Qt 5.13.1 regression known so far:

 * https://bugreports.qt.io/browse/QTBUG-77364

Applying the fix doesn't help with this issue. BTW, Tumbleweeds Qt 5.13.1 
carries a patch for this already:

    0001-QWidget-setFocusProxy-adjust-focus-widget-properly.patch

but only QWebEngine related issues are reported so far concerning this.

Reverting this, as well as reverting 

    https://codereview.qt-project.org/c/qt/qtbase/+/268743

doesn't solve this issue.

Another test, using Qt 5.14 Beta 3 from

http://download.opensuse.org/repositories/KDE:/Medias/images/iso/?
P=*5.14.*.iso

shows the same behavior. Hence, it is to be expected, that any new Qt version 
will suffer from this issue.

Further investigation showed some churn in the src/widgets/kernel/qwidget.cpp 
module, related to focus and focus proxies during this year, so it's very 
likely to be a Qt regression.

@Detlev: have your tried to reproduce the issue already? 

I've tried some hacks on QScintilla/Editor.py, but no cure so far..

Sorry && Cheers,
Pete