Fluent: managed titlebar more accurate.

src/Avalonia.Themes.Default/CaptionButtons.xaml

@@ -4,7 +4,7 @@
     <Setter Property="MaxHeight" Value="30" />
     <Setter Property="Template">
       <ControlTemplate>
-        <StackPanel Spacing="2" Margin="0 0 7 0" VerticalAlignment="Stretch" TextBlock.FontSize="10" Orientation="Horizontal">
+        <StackPanel Spacing="2" VerticalAlignment="Stretch" TextBlock.FontSize="10" Orientation="Horizontal">
           <StackPanel.Styles>
             <Style Selector="Panel">
               <Setter Property="Width" Value="45" />
@@ -57,10 +57,14 @@
   <Style Selector="CaptionButtons:maximized Panel#PART_RestoreButton Path">
     <Setter Property="Data" Value="M2048 410h-410v-410h-1638v1638h410v410h1638v-1638zM1434 1434h-1229v-1229h1229v1229zM1843 1843h-1229v-205h1024v-1024h205v1229z" />
   </Style>
+  <Style Selector="CaptionButtons Panel#PART_FullScreenButton Path">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
   <Style Selector="CaptionButtons Panel#PART_FullScreenButton Path">
     <Setter Property="Data" Value="M2048 2048v-819h-205v469l-1493 -1493h469v-205h-819v819h205v-469l1493 1493h-469v205h819z" />
   </Style>
   <Style Selector="CaptionButtons:fullscreen Panel#PART_FullScreenButton Path">
+    <Setter Property="IsVisible" Value="True" />
     <Setter Property="Data" Value="M205 1024h819v-819h-205v469l-674 -674l-145 145l674 674h-469v205zM1374 1229h469v-205h-819v819h205v-469l674 674l145 -145z" />
   </Style>
   <Style Selector="CaptionButtons:fullscreen Panel#PART_RestoreButton, CaptionButtons:fullscreen Panel#PART_MinimiseButton">

src/Avalonia.Themes.Fluent/Controls/CaptionButtons.xaml

@@ -3,7 +3,7 @@
     <Setter Property="MaxHeight" Value="30" />
     <Setter Property="Template">
       <ControlTemplate>
-        <StackPanel Spacing="2" Margin="0 0 7 0" VerticalAlignment="Stretch" TextBlock.FontSize="10" Orientation="Horizontal">
+        <StackPanel Spacing="2" VerticalAlignment="Stretch" TextBlock.FontSize="10" Orientation="Horizontal">
           <StackPanel.Styles>
             <Style Selector="Panel">
               <Setter Property="Width" Value="45" />
@@ -56,10 +56,14 @@
   <Style Selector="CaptionButtons:maximized Panel#PART_RestoreButton Path">
     <Setter Property="Data" Value="M2048 410h-410v-410h-1638v1638h410v410h1638v-1638zM1434 1434h-1229v-1229h1229v1229zM1843 1843h-1229v-205h1024v-1024h205v1229z" />
   </Style>
+  <Style Selector="CaptionButtons Panel#PART_FullScreenButton Path">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
   <Style Selector="CaptionButtons Panel#PART_FullScreenButton Path">
     <Setter Property="Data" Value="M2048 2048v-819h-205v469l-1493 -1493h469v-205h-819v819h205v-469l1493 1493h-469v205h819z" />
   </Style>
   <Style Selector="CaptionButtons:fullscreen Panel#PART_FullScreenButton Path">
+    <Setter Property="IsVisible" Value="True" />
     <Setter Property="Data" Value="M205 1024h819v-819h-205v469l-674 -674l-145 145l674 674h-469v205zM1374 1229h469v-205h-819v819h205v-469l674 674l145 -145z" />
   </Style>
   <Style Selector="CaptionButtons:fullscreen Panel#PART_RestoreButton, CaptionButtons:fullscreen Panel#PART_MinimiseButton">