setting duration of silence generated impossible

Hi everyone !
I am using a Macbookpro 10.6 with Audacity 2.1.3.
When I try to generate a silence in the middle of a piece, Audacity opens a window where I am supposed to set the number of seconds, minutes, etc, with 4 buttons. Normally, clicking on one of the default numbers, say 0, one can enter the digit desired. Except that it does not change, although my keyboard is working fine. I used to be able to navigate thru the digits, highlight the one I want to change and that was it. Now, it is impossible. That feature is important to me in language learning, to get time to repeat the phrase I am practicing. I rebooted the computer, no result. Even resetting the factory default (silence = 30 seconds) doesn’t work.
Should I desinstall - reinstall Audacity ?
Thank you very much

And there in one post you have the problem with using an older version of Audacity.

It works fine on my 10.9.5 machine using Audacity 2.2.1
Screen Shot 2018-01-25 at 10.24.35.png
Has it ever worked? You can get 2.2.1 from here.


Thank you for the answer. I did install the 2.2.1 version of audacity.
I succeeded in generating a silence, but not with the old way (highlighting a digit, entering a number did not work).
Instead, after highlighting the digit, I used my keyboard up arrow, as recommended, and that did it !
Hurray Audacity, a wonderful program !