Submenus not working on mobile

[pneumaticdeath]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

When I have menuItmes with child menus they can't be accessed when in a mobile layout

How to reproduce

1. Run code below with --tags miobile
2. Select menu Main
3. Select menu Foo
4. Unable to select Bar or Baz menu

Screenshots

Example code

package main

import (
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	a := app.New()
	w := a.NewWindow("Multi layered menus")

	entry := widget.NewEntry()

	barMI := fyne.NewMenuItem("Bar", func() { entry.Text = "Bar"; entry.Refresh() })
	bazMI := fyne.NewMenuItem("Baz", func() { entry.Text = "Baz"; entry.Refresh() })
	barbazMenu := fyne.NewMenu("Foo", barMI, bazMI)
	fooMI := fyne.NewMenuItem("Foo", func() {})
	fooMI.ChildMenu = barbazMenu
	fooMenu := fyne.NewMenu("Main", fooMI)
	mainMenu := fyne.NewMainMenu(fooMenu)

	w.SetMainMenu(mainMenu)
	w.SetContent(entry)

	w.ShowAndRun()
}

Fyne version

v2.5.3

Go compiler version

1.23.4

Operating system and version

macOS Sonoma 14.6.1

Additional Information

works fine in desktop mode

[andydotxyz]

Your fooMI has an action associated with it (the empty function) so it cannot open the submenu.

Replace that with nil and the code works.

	barMI := fyne.NewMenuItem("Bar", func() { entry.Text = "Bar"; entry.Refresh() })
	bazMI := fyne.NewMenuItem("Baz", func() { entry.Text = "Baz"; entry.Refresh() })
	barbazMenu := fyne.NewMenu("Foo", barMI, bazMI)
	fooMI := fyne.NewMenuItem("Foo", nil)
	fooMI.ChildMenu = barbazMenu
	fooMenu := fyne.NewMenu("Main", fooMI)
	mainMenu := fyne.NewMainMenu(fooMenu)

[pneumaticdeath]

Then I'd classify this as a documentation bug, since the behavior is inconsistent with desktop.

[andydotxyz]

Consistency is more important than better docs in this situation I think, opened a PR to resolve that - sorry for the confusion...

[andydotxyz]

Fixed on develop. Beware that we are going through some threading changes there right now so I wouldn't switch immediately but in a couple of days it should be safer - we are making a smoother migration path so that health warnings are not required ;)