QMenubar option to show/hide itself

[Kingston1]

This pull request brings a minor new feature to the QMenubar View section. It implements the ability to show and hide menubar itself. This feature is basically 1:1 copy of the functionality that is quite common in modern menubars, but the best examples are probably Mozilla Firefox and Thunderbird.

When menubar is hidden, it can be toggled hidden/visible with Alt key press.

Also note that this feature does not apply to macOS.

Known Issues:
This is just a minor issue and I don't consider it a merge blocker. Qt eats the QMenubar automated focus that comes default when pressing Alt. It should select the first QMenubar element automatically, but when the menubar is changed from hidden to visible this does not happen. It works fine when menubar is already visible - which is the default so nothing broken there at least. I did all kinds of setFocus experiments around the eventFilter, but none worked this far. This issue is cross-platform and seems like a bug in Qt internal event propagation.

Screenshots

The new menu action:

Here menu is hidden:

Testing strategy

Manual tests with the UI itself. Regularly comparing functionality between this and Mozilla Firefox and Thunderbird.
Could not find places to unit test this as QtWidgets are not designed for that at all.

Tested on Ubuntu 22.04.4 and Windows 11.

Type of change

• ✅ New feature (change that adds functionality)

[droidmonkey]

@Kingston1 what do you think of adding this:

if (menubar->isVisible()) {
    menubar->setActiveAction(mainWindow->m_ui->menuFile->menuAction());
}

This will cause the Database menu to pop out when Alt is pressed. It's definitely more than focusing the menu, but it does work nicely. I also couldn't get the focus to work no matter what.

[Kingston1]

@Kingston1 what do you think of adding this:

if (menubar->isVisible()) {
    menubar->setActiveAction(mainWindow->m_ui->menuFile->menuAction());
}

This will cause the Database menu to pop out when Alt is pressed. It's definitely more than focusing the menu, but it does work nicely. I also couldn't get the focus to work no matter what.

I did exactly this as part of the experiments. But it's not like Firefox or Thunderbird which just shows the plain menu. Possibly it's even a bit distracting as it's not necessarily what the user is looking for. Since there are 6 top level menu items, it's statistically unlikely the correct choice.

I am not completely against it, as it does indeed bring the keyboard focus, but it also was more than I was used to as UI information.

[droidmonkey]

Without that option, you don't gain focus at all and are forced to use the mouse. Statistics doesn't really apply since we aren't guessing what the user wants to focus on, but it's the same behavior as regular alt (database menu has focus) just that it appears. I actually like it a little more, one less key press. Navigating to the other 5 menus is a simple arrow key away.

I also added some protection from false activations if the user is actually pressing alt+tab or similar key combo.