Only show bg on expanded file headers in git diff panel

packages/app/src/components/git-diff-pane.tsx

@@ -207,6 +207,7 @@ const DiffFileHeader = memo(function DiffFileHeader({
     <View
       style={[
         styles.fileSectionHeaderContainer,
+        isExpanded && styles.fileSectionHeaderExpanded,
       ]}
       onLayout={(event) => {
         layoutYRef.current = event.nativeEvent.layout.y;
@@ -1192,6 +1193,9 @@ const styles = StyleSheet.create((theme) => ({
   fileSectionHeaderContainer: {
     overflow: "hidden",
   },
+  fileSectionHeaderExpanded: {
+    backgroundColor: theme.colors.surface1,
+  },
   fileSectionBodyContainer: {
     overflow: "hidden",
     backgroundColor: theme.colors.surface2,