Wayland - Menu scrolling broken

[DMJC]

Expected behaviour

in Wayland when you have more menu items than screen space e.g in Applications -> Internet there is an option in X11 to scroll through the menu to view items which don't fit on the screen.

Actual behaviour

Scrolling doesn't work, and the arrow to scroll down through the menu never appear.

Steps to reproduce the behaviour

Create a menu in mate-panel with more items than will fit on the screen.

MATE general version

1.27.1

Package version

1.27.1-2

Linux Distribution

Debian Trixie 13 (prerelease)

Link to bugreport of your Distribution (requirement)

[lukefromdc]

Just confirmed it here by setting window scaling to 3x in wayfire

[lukefromdc]

Wondering if this might be fallout from work years ago to keep scrollbars from appearing when adequate space is available. There were real problems with this somewhere around 8 years ago after a GTK change. Whatever the fix is it will probably have to be wayland specific to avoid putting scrollbars on x11 menus with adequate space.

[Hagar01]

Still a problem in 1.28

[lukefromdc]

So far I have been unable to find out where this is happening. Do you have similar issues with any other GTK 3 apps in wayland with a long menu and scaling? If so it might be a GTK issue, if not the problem's somewhere in caja

[Hagar01]

I searched for an app that uses GTK 3 and found Terminus.
Very simple.
I opened the preferences and placed it near the top edge - the menu showed the scroll arrows and scrolled up until the entire menu was on the screen - then they disappeared.
I am yet to find a GTK 3 app with a longer menu.

[Hagar01]

OK, pavucontrol is GTK-3 and GTK-3 is linked to wayland.
setting the dpi to 1.5 shrank my display.
One of the settings then went full screen and then when the menu scrolled to fill the screen the same behaviour occurred.
So it appears to be a GTK3 issue.

[lukefromdc]

There have been muliple rounds of menu scrolling issues with GTK3 back when it was under active development. Some problems were fixed at GTK, some worked around, but as I recall nothing ever fixed all of them at once even on Xorg. Since GNOME has replaced GtkMenu with popovers https://docs.gtk.org/gtk4/migrating-3to4.html#consider-porting-to-the-new-list-widgets I suspect no further development attention will go to GtkMenu unless there are a lot of complaints about this

[Hagar01]

I would then assume that moving GtkMenu, GtkMenuBar and GtkMenuItem to GtkPopoverMenu and GtkPopoverMenuBar would be a priority, although complex.

[lukefromdc]

We have no intention of doing that at this time. Getting popovers themed so they would look exactly the same would be a bear of a job and migjt be impossible.I can make them look pretty in my own theme easily enough, but I suspect millions of users would disagree. If GtkMenu is being allowed to bitrot it could be reimplementrd, but that's also a big job. We've already had to reimplement GtkImageMenuItem.