How do I make horizontal scroll bar appear?

I do want autohide but I want a hotkey to make them appear when necessary. also can I enable scroll with arrows?

Sorry, neither of these are possible. You might want to send email to to request these.

Side note: just in case it’s helpful and you aren’t already aware, the Page Up and Page Down keys do work for scrolling vertically in full pages.

Vertical scrolling is not a problem because I can use the mousewheel.

Ah, if mousewheel is adequate, note that shift-mousewheel scrolls horizontally. (That’s a system behavior.)