Merge pull request #4377 from rumkit/fixes/4359-combobox-placeholder-foreground

Updated ComboBox placeholder default foreground and added template binding

src/Avalonia.Themes.Default/ComboBox.xaml

@@ -25,7 +25,7 @@
     <Setter Property="VerticalContentAlignment" Value="Center" />
     <Setter Property="Padding" Value="4" />
     <Setter Property="MinHeight" Value="20" />
-    <Setter Property="PlaceholderForeground" Value="{DynamicResource ComboBoxPlaceHolderForeground}" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource ThemeForegroundBrush}" />
     <Setter Property="Template">
       <ControlTemplate>
         <Border Name="border"
@@ -39,6 +39,7 @@
                        VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                        Margin="{TemplateBinding Padding}"
                        Text="{TemplateBinding PlaceholderText}"
+                       Foreground="{TemplateBinding PlaceholderForeground}"
                        IsVisible="{TemplateBinding SelectionBoxItem, Converter={x:Static ObjectConverters.IsNull}}" />
             <ContentControl Content="{TemplateBinding SelectionBoxItem}"
                             ContentTemplate="{TemplateBinding ItemTemplate}"

src/Avalonia.Themes.Fluent/ComboBox.xaml

@@ -79,6 +79,7 @@
                      VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                      Margin="{TemplateBinding Padding}"
                      Text="{TemplateBinding PlaceholderText}"
+                     Foreground="{TemplateBinding PlaceholderForeground}"
                      IsVisible="{TemplateBinding SelectionBoxItem, Converter={x:Static ObjectConverters.IsNull}}" />
           <ContentControl x:Name="ContentPresenter"
                           Content="{TemplateBinding SelectionBoxItem}"