No resize of left sidebar after reshow
Restore sizes after sidebar reshow
fixes #568
Fix PerformanceManager curve disappear

.. truncating the front of the sts/lts arrays also
   truncated the xday array which mean't it didn't
   start from 0.

.. left code in there, but commented out with a
   comment to explain in case anyone is tempted to
   add it back in the future.