Good and important question, yes a couple of things to consider:
1.) There is no Auto-Save functionality in Jama, if the UI is refreshed or if you click into another comment without submitting the current comment, you will lose your work.
2.) There is also a Session Timeout function you should be aware of, by default it is set to 120 minutes but many companies make requests to make it shorter or longer (dependent on organizational needs). If the Jama UI senses that it is "idle" for the allotted time then it will do a session timeout and you should be able to just refresh and log back in stepping in where you left off. Please note: that the session timeout doesn't recognize that you are "working" when you are in the Rich Text Editor (like the comment section). The session timeout function will restart the timer when you "submit" the work. If you let the session lapse, there will be another window prompting you to renew your session. Just to double-check I experimented with this in my own version of Jama and when I re-logged in, my un-submitted comment was still there. I just wanted to make you aware of this.
To be on the safe side, if you know that you have Reviewers who make long comments over a long period of time, I would tell them that Jama will only allow you to work on one comment at a time, and they need to submit it in order for it to save. I would also increase the Session Timeout time (because pop-ups.....).
I hope this helps!
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