{Linked:Bug9162780} Scroll bar are not visible in code editor pane in High contrast Desert and Aquatic mode.: A11y_MonacoEditor_Usability

GitHubTags:

#A11yTCS; #A11ySev4; #A11yUsable; #Desktopweb; #Win11; #Visual Studio Code Client; #VisualStudioCode-Web-Apr2021; #a11y-monacoeditor; #Linked:Bug9162780; #Linked:Bug9890270;

Environment Details:

#URL: Monaco Editor (microsoft.github.io)
Application name: Monaco Editor
Browser: Chromium Edge Version 132.0.2945.0 (Official build) dev (64-bit)
Windows 11 Enterprise (Version 23H2)  
OS build: 22631.4169

Repro Steps:

1. Hit the URL: https://microsoft.github.io/monaco-editor/playground.html?source=v0.40.0-dev.20230707#XQAAAAJzAQAAAAAAAABBqQkHQ5NjdMjwa-jY7SIQ9S7DNlzs5W-mwj0fe1ZCDRFc9ws9XQE0SJE1jc2VKxhaLFIw9vEWSxW3yscwzfibW_1uhs0-3YGTBOsVJ4S4FwfCDQb5-2uUHXTVAefbVSd9IzaZ_vv9VR9KugsKimARHSWlrTPOQHROITHxmAetfeRrm3VHdSe7_Etv6WpgzlH4vE8EOD3EPhJDl6tDpOO8RxKZbUytKns3T0NFFloo9Q21KsEBT298I6cyZc5-Glup9UHU6QTpv2Hjab6pZzB3ZO2RH-WGhzXse2-hNlgz6zCgsG8AjiqGg0ZzWzND7z09NmCQOQd6pfkNvO2zmMzFvHpTY8RFEy1urlQcQMb1HHLEESBi8m3Rr3UzFlKzY51hfYcz__QCePc.
2. TAB to Monaco editor.
3. Apply high contrast desert theme.
4. Observe the issue

Actual Results:

Scroll bar are not visible in code editor pane in High contrast Desert and Aquatic mode.

Expected Results:

Scroll bar should be visible in code editor pane in High contrast Desert and Aquatic mode.

User Impact:

Color blind users will not be able to see the scrollbars and might face difficulty to interact with editor.

Attachment:

https://github.com/user-attachments/assets/e25f7f2a-1d8d-4432-8edf-f010f3101c7b

Start with the linked Monaco Editor playground and reproduce the missing scrollbar in the High Contrast Desert and Aquatic themes using the stated Edge and Windows environment. Trace the editor theme and scrollbar styling from the playground entry point, then verify that scrollbars are visible and usable in both themes without regressing the other editor themes.