What do the colour codes on the Planner job boxes mean?

The colour coding for the jobs on the "Planner" calendar are:

Red - overdue
Green - due today/tomorrow
Blue - later in the week
Grey and struck through - jobs that have been marked as "Done"
Grey and cannot be moved or amended - projected jobs (the previous clean in the schedule has not been marked as "Done/Missed")
Grey - those due next week and further ahead that can be moved/amended