Fix drop-box colors. (#5291)

packages/devtools_app/lib/src/shared/common_widgets.dart

diff --git a/packages/devtools_app/lib/src/shared/common_widgets.dart b/packages/devtools_app/lib/src/shared/common_widgets.dart
index c2f77d7..e18abcb 100644
--- a/packages/devtools_app/lib/src/shared/common_widgets.dart
+++ b/packages/devtools_app/lib/src/shared/common_widgets.dart
@@ -12,6 +12,7 @@
 import 'package:vm_service/vm_service.dart';
 
 import '../screens/debugger/debugger_controller.dart';
+import '../screens/inspector/layout_explorer/ui/theme.dart';
 import 'analytics/analytics.dart' as ga;
 import 'config_specific/launch_url/launch_url.dart';
 import 'console/widgets/expandable_variable.dart';
@@ -1215,6 +1216,8 @@
 
   @override
   Widget build(BuildContext context) {
+    final bgColor = Theme.of(context).colorScheme.backgroundColorSelected;
+
     return RoundedOutlinedBorder(
       child: Center(
         child: Container(
@@ -1231,6 +1234,7 @@
               style: style,
               selectedItemBuilder: selectedItemBuilder,
               items: items,
+              focusColor: bgColor,
             ),
           ),
         ),