In Tabs Studio, tabs expand to fill available row space (unless it is the last row of tabs). This is how it looks in VS 2022:
I’ve added the new ShortTabs property that prevents tab expansion:
You can enable it with the following style:
<Style TargetType="TabsStudio:Tabs" BasedOn="{StaticResource DefaultTabsStyle}">
<Setter Property="ShortTabs" Value="True"/>
</Style>
Download link: Tabs Studio v5.0.2.
Tabs Studio Blog (organizing Visual Studio document tabs) 