The Calc tiled rendering is not yet finished, and behaves problematically with most of the documents; for example it shows the content of the cells, but with the next re-render, the cells become empty. It is also not merged to master yet, only lives in a branch... Documents that show these problems are: https://bugs.freedesktop.org/attachment.cgi?id=39898 https://bugs.freedesktop.org/attachment.cgi?id=40895 https://bugs.freedesktop.org/attachment.cgi?id=44570
Calc tiled rendering improved a lot, setting to FIXED. Further problems should be reported case-by-case,