Quick Question on Pocket Outlook's Calendar

[Guest wcr]

Can anyone tell me what the various icons in the Month view on the Calendar denote?

I've got some hollow squares, some solid colour squares, as well as half solid coloured squares.

They seem to randomly relate to appointments I've got saved in there - but it would be good to know what means what!

BTW: I'm using it on a frankly superb SPV E650