Adding issues to epics: the "Add" button improvement.

While adding Issues to Epics in the Epics page, I see the following behaviour:

1. I click the + , paste the Issue's URL and then I click 'Add' - the issue does not get added.
2. I click the + , paste the Issue's URL and then enter a 'space' and then I click Add - the issue gets added.
3. I click the +, paste the Issue's URL and then I click 'Add' twice - the issue gets added.

Ideally, anyone would like to just paste the link and click on 'Add' (might not be mindful of entering a space all the time) This is just a minor thing that can help in better user experience.