With the 'All' or the 'Time spent' tab on view, whenever make a change on the issue (intut work time, make a comment, change assignee...) and then you try to do something to leave this issue (change the URL, make a quick search, follow a link on the issue), you get an anoying confirmation dialog.
This does not happen when modifying the issue while you're on the Comments, Worklogs+, Change history, Activity, Transitions summary or Commits tab.

On a support tickt with atlassian we have reduced it to be a bug with Minyaa JIRA Plugin for Time Management. If I disable this plugin, the bug does not happen.

Besides, and I think it is related to the same problem, when switching to the 'All' tab, a progress bar appears and stays there until page is refreshed, not allowing to see any content on the tab.