Style visibility=HIDDEN has no effect on GTK

[LordOfDragons]

Describe the bug

Using this code:

        self.sel_control = toga.Selection(
            items=[], style=tp.Pack(flex=1), accessor="name",
            on_change=self.on_selection_control_sel_changed)
        box.add(self.sel_control)
        self.sel_control.style.update(visibility=toga.style.pack.HIDDEN)

The widget is still visible. Makes it impossible to have a box with different widgets showing only the one matching an input type. And no the OptionContainer is not an option since it has tabs and does not guarantee invisibility.

Steps to reproduce

Use the code above. Widget is still visible

Expected behavior

Widget is invisible

Screenshots

No response

Environment

Linux, most recent Toga

Logs

No response

Additional context

No response

[mhsmith]

Thanks for the report. We're currently working on this in #2435, but I'll leave this issue open for ... visibility.