diff --git a/ILSpy/MainWindow.xaml b/ILSpy/MainWindow.xaml
index 7cc334097..5dbd9b720 100644
--- a/ILSpy/MainWindow.xaml
+++ b/ILSpy/MainWindow.xaml
@@ -32,7 +32,7 @@
 				ShowRoot="False"
 				AllowDropOrder="True"
 				AllowDrop="True"
-				BorderThickness="0,1,1,1" Visibility="Visible" />
+				BorderThickness="0" Visibility="Visible" />
 
 		<DataTemplate x:Key="AssemblyListPaneTemplate">
 			<ContentControl Content="{StaticResource AssemblyTreeView}" />
diff --git a/ILSpy/themes/DarkTheme.xaml b/ILSpy/themes/DarkTheme.xaml
index f1125651c..976a981da 100644
--- a/ILSpy/themes/DarkTheme.xaml
+++ b/ILSpy/themes/DarkTheme.xaml
@@ -52,7 +52,7 @@
 	<SolidColorBrush x:Key="{x:Static SystemColors.InactiveBorderBrushKey}" Color="#434346" />
 	<SolidColorBrush x:Key="{x:Static SystemColors.InactiveCaptionTextBrushKey}" Color="#F1F1F1" />
 
-	<SolidColorBrush x:Key="{x:Static styles:ResourceKeys.BorderBrush}" Color="#3F3F46" />
+	<SolidColorBrush x:Key="{x:Static styles:ResourceKeys.BorderBrush}" Color="#9E9E9E" />
 	<SolidColorBrush x:Key="{x:Static styles:ResourceKeys.DisabledBrush}" Color="#2D2D30" />
 	<Color x:Key="{x:Static themes:ResourceKeys.TextMarkerBackgroundColor}">MediumVioletRed</Color>
 	<SolidColorBrush x:Key="{x:Static themes:ResourceKeys.LinkTextForegroundBrush}">CornflowerBlue</SolidColorBrush>
diff --git a/ILSpy/themes/LightTheme.xaml b/ILSpy/themes/LightTheme.xaml
index 4772cfd78..7997c8729 100644
--- a/ILSpy/themes/LightTheme.xaml
+++ b/ILSpy/themes/LightTheme.xaml
@@ -47,6 +47,6 @@
 	<SolidColorBrush x:Key="{x:Static SystemColors.InactiveBorderBrushKey}" Color="#CCCEDB" />
 	<SolidColorBrush x:Key="{x:Static SystemColors.InactiveCaptionTextBrushKey}" Color="#1E1E1E" />
 
-	<SolidColorBrush x:Key="{x:Static styles:ResourceKeys.BorderBrush}" Color="#CCCEDB" />
+	<SolidColorBrush x:Key="{x:Static styles:ResourceKeys.BorderBrush}" Color="#686868" />
 	<SolidColorBrush x:Key="{x:Static styles:ResourceKeys.DisabledBrush}" Color="#EEEEF2" />
 </ResourceDictionary>
\ No newline at end of file