Issue Summary

Custom field option can still be selected in the transition screen even after being disabled as long as the option was the current one when it was disabled.

Steps to Reproduce

• Create a cascading field with parent and child options
  • E.g. A -> B, C -> D
• Set the Parent/Child option as A -> B in an issue
• Disabled the child option B present under A

Expected Results

Though the current value is still displayed in the issue view, it will not be selectable in any other way:

Actual Results

The disabled option is still selectable in transition screens:

Workaround

After setting the value to something else, the value will not be displayed in the transition screen anymore:

Additionally, this behaviour does not occur in the new transition experience.