Bug 483075

Can confirm, in my case when using gimp and it opens any popup window I lost the global menu too.
ie: open and image in gimp go to "File -> export as" the global menu is gone and it doesn't come back after closing the export window.
If you alt tab out and back to gimp the global menu comes back.

Created attachment 167011 [details]
Task Manager, Global Menu and pop-up window

I also noticed that when the global menu disappears, the current window is also not marked as active in the task manager.

I generated a new C++ KDE project with a main window, a toolbar and a main menu from a template in KDevelop, and added a few lines to the signal handler of a toolbar item to pop up a window.

```
    QTimer::singleShot(200, this, [this]() {
            KMessageBox::information(this, i18n("Congratulations, you have solved board"));
    });
```

The pop-up window from `KMessageBox::information` does not appear on the task manager.  When the window pops up, two things may non-deterministically happen to the task manager (See the screen recording in the attachment)

1.  The task manager still highlights the main window as the active task.  (This happens the first time I clicked the toolbar in the video)
2.  The task manager does not highlight *any* window as active. (This happens the second time I clicked the toolbar in the video)

In the first case, the Global Menu applet still shows the menu of the main window; in the second case, the Global Menu applet disappears.

I think the connection between the Task Manager and the Global Menu applet is that the Global Menu applet uses the `TaskManager::TasksModel` (in libtaskmanager) to determine the active window.  So if a glitch happens in the Task Manager, the Global Menu is affected, too.

I also suspect that if a window does not appear in the TaskManager but still has a MenuBar widget, the Global Menu widget will not work for that window even if the window has focus.  I haven't confirmed it, yet.

Created attachment 167080 [details]
Preview window in Qt Designer

There is another way to reproduce it.

1.  Open QtDesigner
2.  Create a new form, using "Main window" as the template
3.  Edit the "MainWindow - untitled" and add some menus in its menu bar (such as "foo" and "bar" as in the screenshot)
4.  Preview (From the menu: "Form" -> "Preview...")

What actually happens is as shown in the screenshot.  The global menu disappeared, and there is no active task highlighted in the task manager.  There is an entry in the task manager for Qt Designer itself, but there is no entry for the preview window (the window with title "MainWindow - [preview] -- Qt Designer").

At this point, if we switch to another app (such as Konsole), and switch back to Qt Designer, then the preview window will be on top of Qt Designer.  But Qt Designer will be high-lighted in the task manager, and the Global Menu applet will show the menu of Qt Designer.  There is no way for Global Menu to show the menu for the preview window.

This confirms with my hypothesis that the Global Menu applet is showing the menu of the highlighted task in the task manager applet.  If a window, for some reasons, does not have an entry in the task manager, its menu will not be shown even if it is the window with focus.

I think that's the root cause of the problem.  The Global Menu applet should determine which window to show menu for by detecting the focused window rather than the active entry in the task manager.

Cool, great analysis! Would you like to work on a code change for that and submit it to KDE?

(In reply to Nate Graham from comment #4)
> Cool, great analysis! Would you like to work on a code change for that and
> submit it to KDE?

I have no prior experience in KDE development and very little in Qt programming, so I can't contribute code for now.  Sorry about that.

I can confirm this bug... it is pretty awful for productivity.  I use Quartus Prime Lite and any time you open some kind of child window in the app, the global menu disappears and does not come back when the window closes.  The only way to get it to come back is to switch focus away from the app and back again.  A couple of important details about this bug:

1.  This bug is WAYLAND ONLY.  X11 still works correctly.  But at this point we are kind of all being forced into Wayland so that's not very helpful anymore.

2.  Focus follows mouse and its variations are not affected by the bug because the global menu is seemingly automatically restored by the mouse's focus.  So people using FFM won't be noticing what a show stopper this bug is.

3. The global menu seems to be disappearing because it is somehow losing connection with the focused app.  In the distribution Garuda KDE Dr460nized (which I am using) the global menu is set up to display the application name, and when nothing is focused (i.e. by clicking on the desktop) it just displays the name "Dr460niszed KDE".  When the global menu disappears, it always says the focused app name is just "Dr460niszed KDE".

4.  Related to #3: There is a less severe symptom of the bug which is probably going unnoticed by most.  Some apps will restore the global menu after closing a child window, but Garuda Linux does not update the focused app name in the global menu.  For example Gimp normally says "GNU Image Manipulation Program" in front of the menu options ("File Edit" etc..) but after the bug occurs it will still have it's menu options but will say "Dr460nized KDE" instead.

Further clarification on #1:

It looks llke the menu disappears maybe because child windows do not have global menu options directly associated with them.  This is a Wayland-only behaviour.  In X11 sessions, the global menu never changes when a child window with no global menu options appears, it consistently shows the main application global menu options.

Hopefully these details help to get this bug fixed as quickly as possible.  For testing I recommend installing Quartus Prime Lite, it's the most unusable thing I'm trying to use at the moment with this bug.  Open the application then try to open a settings/options child window from the global menu (for example: Tools > Options...)

(In reply to Miranda from comment #6)

> 2.  Focus follows mouse and its variations are not affected by the bug
> because the global menu is seemingly automatically restored by the mouse's
> focus.  So people using FFM won't be noticing what a show stopper this bug
> is.

Sorry, I was wrong about this point.  It's "Focus under mouse" and "Focus strictly under mouse" that are not affected.  FFM doesn't reacquire the global menu focus, but the under mouse options seem to actually never lose focus in the first place, because the global menu does not disappear when you open child windows while in those modes.