How do I put the "offline_access" in scope parameter of the authorization URL ?

[Sogeti ATS]

I read all the "OAuth 2.0 authorization code grants (3LO) for apps" and in your answer to "How do I get a new access token, if my access token expires or is revoked?" it says that I have to add "offline_access" to my scope to be able to use refresh tokens, so I tried to find in the "App Management" if I could add directly the scope like all the other ones but there is not the option.
After that I tried to do it manually by adding %20 before the scope since it seems to be the separator that gives me as scopes : 

read%3Ajira-work%20write%3Ajira-work%20manage%3Ajira-project%20manage%3Ajira-configuration%20read%3Ajira-user%20manage%3Ajira-data-provider%20offline_access

But even like that I can't get the refresh token, I wonder if it's because I'm using https://oauthdebugger.com/debug as a redirect_uri to test my requests and if it would actually work if I tried directly in my JavaScript code..

[Sogeti ATS · Accepted solution]

I've found the solution, it was OAuthdebugger that didn't show the refresh tokens, thanks anyway.