Why is a removed downtime code still selectable on an older order?

Why is a removed downtime code still selectable on an older order?

An example

You remove the code "Filter Change" from Line 1 in Manager. Operators no longer
see it when they record a new stop.

You then open an order from last month. One stop on that order was recorded as
"Filter Change". The Reason Code list on that stop still shows "Filter Change",
because the stop already uses the code.

You open a second order from the same week. No stop on it uses "Filter Change",
so the code does not appear.

Where the code appears, and where it does not

1. On a stop that already uses the code: the code appears. You can keep it, or
   reassign it to a different code.
2. On any other stop, on any order: the code does not appear.
3. On a new stop: the code does not appear.

Make sure the code is removed from the line

Follow the steps in How to Remove Downtimes in Bulk through in Manager? 

Before you start, open the code and check its All Work Centres setting.

- If All Work Centres is No, remove the work centre from the code.
- If All Work Centres is Yes, the code applies to every line. Removing one work
  centre has no effect. Contact support before you change this setting.

Hiding a code is not the same as removing it

See steps under option 2 in How do I add downtime codes?

The Loss Codes file in Manager has a column named Display On LineStop
DropdownList, also called Column K. Set it to 0 and operators do not see the
code when they record a stop.

Column K is a setting on the code, not on the line. It applies to every line
that uses the code, at every site in the system.

Use Column K only when you want the code gone from the pick list everywhere. To
remove a code from one line, use the Assign Downtime tab instead. See
How to Remove Downtimes in Bulk through in Manager?