Issue Summary

When an attachment is added in the comments (in text, not visual mode), the "Add" button is greyed out unless a 'Space' or some character is added on the comment box.

This is reproducible on Data Center: Yes

Affected on ,9.0, 9.1.0 . This is not observed in versions 8.22,8.20 

Steps to Reproduce

1. On Jira 9.1, Created a new issue
2. Add an image to the comment (New attachment or an existing attachment) 
3. The add button will greyed out and will be enabled if a character is added on the comment box. 

Expected Results

Actual Results

Workaround

Adding a character on the comment and removing them enables the Add button