Follow up for https://www.noesisengine.com/forums/viewtopic.php?f=3&t=1129 and https://bugs.noesisengine.com/view.php?id=1121

Tab-control focusing using Shift-tab is different from WPF.

<Grid
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
<Button Content="Button 1"/>
<TabControl Margin="0,20">
<TabItem Header="Tab1">
<Button Content="Button Tab 1" Margin="20"/>
</TabItem>
<TabItem Header="Tab2">
<Button Content="Button Tab 2" Margin="10"/>
</TabItem>
</TabControl>
<Button Content="Button 2"/>
</StackPanel>
</Grid>

In WPF pressing Shift+Tab will jump from "Button 2" to "Button Tab 1", then "TabControl", and finally "Button 1";
In Noesis it will go from "Button 2" to "TabControl" and finally to "Button 1", we are incorrectly skipping the content of the TabItem when moving focus backwards.