Order ticks don't appear if there are empty columns omitted

[zestyping]

App version: d4222c4
Screen or dialog: Patient chart

Steps to replicate the problem

1. Open a patient chart that has some empty columns omitted (a gap of two or more days).
2. Add a treatment.
3. Execute the order.

Actual behaviour

Ticks representing the order executions do not appear.

Expected behaviour

Ticks should appear.

Discussion

We know why this is happening—the divisionIndex is incorrectly counted when columns are omitted.