Very basic question

[Tyrannocaster]

But I can't figure out how to find the answer via Search. How do I use the underlined right-mouse-button shortcuts in Thunar? For example, the Rename function has an underlined shortcut of "R", but using lower or upper-case R just opens up what looks like a search field in the bottom of the pane. Ditto for Properties, etc. I have searched for tips on using Thunar in general but still haven't found this, so I must be looking in the wrong place or using the wrong search terms.

Thanks!