Fixed the dropdown behavior

[echo-liang]

Description

This PR includes the following proposed change(s):

• Layout fix in RAN List view
• Fixed the dropdown button behavior, so that when click on the DDL, it automatically highlight the current selection, typing a new value would replace the current value, rather than append to it.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring / Documentation

if your change is a breaking change, please add breaking change label to this PR

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes