Correct a visual error in the ComboBox drop-down list, where black borders appear at both the top and bottom. <img width="202" height="236" alt="Image" src="https://github.com/user-attachments/assets/daebd70b-ffb0-48d3-bb14-f815ab290976" />
Correct a visual error in the ComboBox drop-down list, where black borders appear at both the top and bottom.