TabControl breaks keyboard navigation

[m0n5ter]

Describe the bug

It is impossible to navigate to other tabs using Tab keyboard navigation. Once focus gets inside a TabItem there is no way out.

To Reproduce

Simplest XAML to reproduce

<TabControl>
    <TabItem Header="Tab1">
		<CheckBox>Check1</CheckBox>
    </TabItem>
    <TabItem Header="Tab2">
		<CheckBox>Unreachable</CheckBox>
    </TabItem>
</TabControl>

Second CheckBox cannot be reached with Tab navigation. Basically nothing else can be reached once focus hits any CheckBox

Expected behavior

Pressing Tab on the last control within TabItem should move focus back to TabControl

Avalonia version

11.3.6

OS

Windows

Additional context

No response

[timunie]

https://api-docs.avaloniaui.net/docs/F_Avalonia_Input_KeyboardNavigation_TabNavigationProperty

Please try to set this property.

[m0n5ter]

@timunie I tried that of course. By default it is set to Continue everywhere, which is logical, but just does not work like expected. I was also unable to fix the behavior with any combination of TabNavigation settings

[timunie]

Using your sample and looking into DevTools I can see there is one visual element that has set it to Once:

This seems to be by-design unfortunately.

Avalonia/src/Avalonia.Controls/TabControl.cs

Lines 251 to 252 in 912f916

	// Set TabNavigation to Once on the panel if not already set and
	// forward the TabOnceActiveElement to the panel.

I would suggest to use a TabStrip and a ContentControl, where the Content is bound to the SelectedItem. This way you should have more control.

I'll keep this issue open for discussing if we want to update the API to allow more Tab-Options.