feat: utilize combobox popup resources.

src/Ursa.Themes.Semi/Controls/DatePicker.axaml

@@ -74,7 +74,7 @@
                                 Placement="BottomEdgeAlignedLeft"
                                 PlacementTarget="{TemplateBinding}">
                                 <Border
-                                    Margin="8"
+                                    Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                     Padding="8"
                                     Background="{DynamicResource ComboBoxPopupBackground}"
                                     BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"

src/Ursa.Themes.Semi/Controls/DateRangePicker.axaml

@@ -82,7 +82,7 @@
                             Placement="BottomEdgeAlignedLeft"
                             PlacementTarget="Background">
                             <Border
-                                Margin="8"
+                                Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                 Padding="8"
                                 HorizontalAlignment="Stretch"
                                 Background="{DynamicResource ComboBoxPopupBackground}"

src/Ursa.Themes.Semi/Controls/DateTimePicker.axaml

@@ -73,7 +73,7 @@
                                 Placement="BottomEdgeAlignedLeft"
                                 PlacementTarget="{TemplateBinding}">
                                 <Border
-                                    Margin="8"
+                                    Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                     Padding="8"
                                     Background="{DynamicResource ComboBoxPopupBackground}"
                                     BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"

src/Ursa.Themes.Semi/Controls/MultiComboBox.axaml

@@ -110,7 +110,7 @@
                             IsOpen="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsDropDownOpen, Mode=TwoWay}"
                             PlacementTarget="PART_RootGrid">
                             <Border
-                                Margin="0,4"
+                                Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                 HorizontalAlignment="Stretch"
                                 Background="{DynamicResource ComboBoxPopupBackground}"
                                 BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"

src/Ursa.Themes.Semi/Controls/TimePicker.axaml

@@ -159,7 +159,7 @@
                                 Placement="BottomEdgeAlignedLeft"
                                 PlacementTarget="Background">
                                 <Border
-                                    Margin="0,4"
+                                    Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                     HorizontalAlignment="Stretch"
                                     Background="{DynamicResource ComboBoxPopupBackground}"
                                     BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"

src/Ursa.Themes.Semi/Controls/TimeRangePicker.axaml

@@ -83,7 +83,7 @@
                             Placement="BottomEdgeAlignedLeft"
                             PlacementTarget="Background">
                             <Border
-                                Margin="0,4"
+                                Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                 HorizontalAlignment="Stretch"
                                 Background="{DynamicResource ComboBoxPopupBackground}"
                                 BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"

src/Ursa.Themes.Semi/Controls/TreeComboBox.axaml

@@ -111,7 +111,7 @@
                         WindowManagerAddShadowHint="False">
                         <Border
                             Name="PopupBorder"
-                            Margin="0,4"
+                            Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                             Background="{DynamicResource ComboBoxPopupBackground}"
                             BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"
                             BorderThickness="{DynamicResource ComboBoxPopupBorderThickness}"

src/Ursa.Themes.Semi/Index.axaml

@@ -15,6 +15,8 @@
                 <ResourceInclude Source="Themes/Shared/_index.axaml" />
                 <ResourceInclude Source="Locale/zh-cn.axaml" />
             </ResourceDictionary.MergedDictionaries>
+            <!-- This resource definition is from Semi Avalonia 11.2.1. This can be removed after Ursa dependency is higher than Avalonia 11.2.1 -->
+            <Thickness x:Key="ComboBoxPopupBorderMargin">4</Thickness>
         </ResourceDictionary>
     </Styles.Resources>