Hello,
I am using JIRA software hosted on Atlassian.com. I cannot figure out how to add a linked issue to an issue that already exists, but has no linked issues yet. Here is a screenshot to a task, that already has any linked issues, because they were added at task creation time. For this issue, I can link an issue:

Now here is an issue, that has no linked issues created at task creation time. I now cannot add any new linked issues to it, since there is no "+" button:

Also, clicking show more will not show any additional linking options.
I would appreciate all help.