When exporting submissions to an excel file on a site with a lot of student’s and/or assignments an empty file will be exported. The critical amount of data is a bit below 10.000 rows - (64000 styled cells). The issue happens due to an illegal number of style definitions on the excel file, due to the same style being created for each cell - the style is created and added to the style while looping through the entries. A proposed solution would be to move the creation of the style out of the loops and only add it to the cell within the loop. This should also improve performance on smaller data sets where the the download does not “blow up”.

The sakai property timesheet.sites.allowed=all should be set to be able to use the download on Assignments by students.
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