[Octave-bug-tracker] [bug #53276] GUI: undocked panes cannot be moved, or resized along upper border

[Dan Sebald]

Follow-up Comment #104, bug #53276 (project octave):

Record discussion length?  Probably not even close, hee-hee.  Plus, we've
uncovered maybe three other significant bugs, so divide that post-length by
three.  And now I've uncovered a fourth significant bug (Qt), mentioned here:

https://savannah.gnu.org/bugs/?53807

I think we've managed pretty well with so many unsuspected significant bugs in
the mix.  One keeps thinking it is programmer-error when in fact it's
something outside their control.

I've spent some time going over the code and created a new version (attached)
that I believe is ready to go.  It has maybe a half-dozen bug fixes and
improvements, e.g., a crash-bug due to deleted variable window and refocusing
the variable editor, better restoring of geometry in the fullscreen-to-docked
mode, etc.

The most significant is dealing with another bug in KDE/Qt (Qt's
responsibility).  It has to due with QDockWidget mouse-drag floated windows
being un-focusable.  (The bug manifests in the variable_dock_widget objects.) 
I basically had to use the same approach as was used for drag-float of the
octave_dock_widgets, but slight variation on the theme.  The solution
circumvents the problem by redocking and refloating the drag-float
QDockWidget, i.e., turn it from a drag-float window to a direct-float window. 
If one pays close attention, the undock-button-click floated windows have a
quick display while the drag-floated windows flash  off and on.

The bug exists in all KDE themes.  To see a before and after comparison, go to
the file variable-editor.h (after having done the patch command) and change

#define QTBUG_44813_FIX_VERSION 0x999999

to

#define QTBUG_44813_FIX_VERSION 0x009999

and recompile.  Just create some variable panels:


>> x = eye(3); openvar x; y = magic(5); openvar y; z = x; openvar z;


and drag the title bar to float.

The number 0x999999 is meant to be replaced by whatever version of Qt it is
for which the developers provide a fix.  (Well, I sure hope it is a Qt version
and not something KDE-related.)

As for the KDE-with-Oxygen theme non-movable windows bug, it seems to have
gotten about as much response from KDE developers as what I got from
OpenGL/swrast/Gallium developers a few years back.  But unlike those bugs, I'm
not going to dig into any KDE window manager code and try building a window
manager to test and debug.

So the summary is that with the latest patch everything looks pretty good, but
avoid using Oxygen on KDE.  I won't look at this one much more.

(file #44067)
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Additional Item Attachment:

File name: octave-float_as_toplevel-djs2018may02.patch Size:52 KB


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