How to delete Safari history ?

I click on Show All History, then on the top right hand side there is the Clear History icon, but it is not highlighted, I click on it but nothing happens.

I also tried this: Command all > right click > delete, but it does not delete. Instead it just reverts to highlighting one line. I right click on that one line > delete , but to no avail.

I also tried this: Command all > drag to trash bin , but that doesn't work either.

I wonder if I need to change some settings on the computer ?

I wonder if there are analysts who have prevented me from deleting my browsing history so that they can track my browsing history ?