Hello @Guillaume Dewaghe ,
As described at the document- VisualElement Access Keys on Windows - Xamarin | Microsoft Learn: This UWP platform-specific is used to specify an access key for a VisualElement. But the inheritance of ToolbarItem (Object->BindableObject->Element->BaseMenuItem->MenuItem->ToolbarItem) doesn't include
VisualElement, you cannot set the Access key for ToolbarItem by this way.
ToolbarItem class is a special type of button, you could try to custom the
NavigationPage.TitleView and set the attached property to a layout class that contains multiple buttons, then set the Access key for the Button. For more details, you can refer to Displaying Views in the Navigation Bar and Xamarin.Forms ToolbarItem - Xamarin | Microsoft Learn.
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