How to delete files in the Content brower espesically c++ source codes.

Hello guys,

I’ve met a problem now when deleting source codes in Content Browser.
When the pop-up menu opens by clicking RMB on an item in Content Browser, some menu items including “Delete” are grayed on Windows as the attached image.
I also work on Mac but I can’t find a way of opening the pop-up menu in Content browser there.

FYI I’m using 3.7.4 version.

Do you know how to enable the grayed menu items on Windows and open the pop-up menu on Mac?