Xamlify this too

Content.Client/Preferences/UI/HighlightedContainer.xaml

@@ -0,0 +1,11 @@
+<PanelContainer
+    xmlns="https://spacestation14.io"
+    xmlns:graphics="clr-namespace:Robust.Client.Graphics;assembly=Robust.Client">
+    <PanelContainer.PanelOverride>
+        <graphics:StyleBoxFlat BackgroundColor="#2F2F35"
+                               ContentMarginTopOverride="10"
+                               ContentMarginBottomOverride="10"
+                               ContentMarginLeftOverride="10"
+                               ContentMarginRightOverride="10"/>
+    </PanelContainer.PanelOverride>
+</PanelContainer>

Content.Client/Preferences/UI/HighlightedContainer.xaml.cs

@@ -0,0 +1,14 @@
+using Robust.Client.AutoGenerated;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.UserInterface.XAML;
+
+namespace Content.Client.Preferences.UI;
+
+[GenerateTypedNameReferences]
+public sealed partial class HighlightedContainer : PanelContainer
+{
+    public HighlightedContainer()
+    {
+        RobustXamlLoader.Load(this);
+    }
+}