Recently Timesheet Reports and Gadgets for Jira Server has been upgraded to a latest version (4.2.1) and since then work log pop-up suddenly disappears and not able to see anything when we hover on Work log data on Time sheet gadget on Dashboard.
This is a side effect of a recent fix to avoid out of memory issues. No worklog details will be displayed if the count of worklogs exceed 1000.
Please consider reducing period displayed to weekly and possibly also the amount of users displayed. This should render the popup to display.