How do you select a static mesh element by clicking the left mouse button in the running mode?

Can you send me your test file for reference?
My Email is 576435459@qq.com

Iā€™m really troubled.

Sure thing, I can send you the project. But one last thing, could you double check the material slot name and material name in your mesh - they need to be the same for this to work properly:

228225-untitled.png

Sent you the project. Good luck!

Thank you very much. 么么哒ļ¼~