When I booted my machine I somehow got the time set 6 hours in the
future.  I recovered by doing "chronyc makestep", but workrave still
thought the next microbreak and rest break were due so many minutes
futureward of the time when it started up, i.e. 6hr 55min in the future
of the corrected time.  

Maybe on a negative time jump, workrave should add the negative delta
to the due date of the rest break and microbreak, and something 
equivalent for the daily limit.  Alternatively, in case of generic
screwups, there could be a button in the GUI to make it recompute
the dates and daily limit.