fix: hotkey to stage/unstage/discard selected hunk only works in the very FIRST text diff view instance (#2410)

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Views/TextDiffView.axaml

@@ -100,7 +100,7 @@
     </ContentControl>
 
     <StackPanel x:Name="Popup" IsVisible="False" Orientation="Horizontal" VerticalAlignment="Top" HorizontalAlignment="Right" Effect="drop-shadow(0 0 8 #80000000)">
-      <Button Classes="flat" BorderBrush="{DynamicResource Brush.FlatButton.FloatingBorder}" Click="OnStageChunk" HotKey="{OnPlatform Ctrl+S, macOS=⌘+S}" IsVisible="{Binding Option.IsUnstaged}">
+      <Button Classes="flat" x:Name="BtnStageChunk" BorderBrush="{DynamicResource Brush.FlatButton.FloatingBorder}" Click="OnStageChunk" IsVisible="{Binding Option.IsUnstaged}">
         <TextBlock>
           <Run Text="{DynamicResource Text.Hunk.Stage}"/>
           <Run Text=" "/>
@@ -111,7 +111,7 @@
         </TextBlock>
       </Button>
 
-      <Button Classes="flat" BorderBrush="{DynamicResource Brush.FlatButton.FloatingBorder}" Click="OnUnstageChunk" HotKey="{OnPlatform Ctrl+U, macOS=⌘+U}" IsVisible="{Binding Option.IsUnstaged, Converter={x:Static BoolConverters.Not}}">
+      <Button Classes="flat" x:Name="BtnUnstageChunk" BorderBrush="{DynamicResource Brush.FlatButton.FloatingBorder}" Click="OnUnstageChunk" IsVisible="{Binding Option.IsUnstaged, Converter={x:Static BoolConverters.Not}}">
         <TextBlock>
           <Run Text="{DynamicResource Text.Hunk.Unstage}"/>
           <Run Text=" "/>
@@ -122,7 +122,7 @@
         </TextBlock>
       </Button>
 
-      <Button Classes="flat" BorderBrush="{DynamicResource Brush.FlatButton.FloatingBorder}" Margin="8,0,0,0" HotKey="{OnPlatform Ctrl+D, macOS=⌘+D}" Click="OnDiscardChunk" IsVisible="{Binding Option.IsUnstaged}">
+      <Button Classes="flat" x:Name="BtnDiscardChunk" BorderBrush="{DynamicResource Brush.FlatButton.FloatingBorder}" Margin="8,0,0,0" Click="OnDiscardChunk" IsVisible="{Binding Option.IsUnstaged}">
         <TextBlock>
           <Run Text="{DynamicResource Text.Hunk.Discard}"/>
           <Run Text=" "/>

src/Views/TextDiffView.axaml.cs

@@ -1467,14 +1467,21 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
             {
                 if (SelectedChunk is { } chunk)
                 {
+                    var syscmd = OperatingSystem.IsMacOS() ? "Cmd" : "Ctrl";
                     var top = chunk.Y + 4;
                     var right = (chunk.Combined || !chunk.IsOldSide) ? 26 : (Bounds.Width * 0.5f) + 26;
                     Popup.Margin = new Thickness(0, top, right, 0);
                     Popup.IsVisible = true;
+                    BtnStageChunk.HotKey = KeyGesture.Parse($"{syscmd}+S");
+                    BtnUnstageChunk.HotKey = KeyGesture.Parse($"{syscmd}+U");
+                    BtnDiscardChunk.HotKey = KeyGesture.Parse($"{syscmd}+D");
                 }
                 else
                 {
                     Popup.IsVisible = false;
+                    BtnStageChunk.HotKey = null;
+                    BtnUnstageChunk.HotKey = null;
+                    BtnDiscardChunk.HotKey = null;
                 }
             }
         }