I have a situation where I want to prevent (some) users from changing a picklist field once it has been set to a specific value.
I'm trying to create a validation rule that fires if the field is already set to that value - based on docs I thought that I should use:
so that a validation error occurs when the picklist value is 'Filled'.
When I try this, and I try setting the picklist value to 'Filled' so that I can then try changing it, I get a
FIELD_CUSTOM_VALIDATION_EXCEPTION error - never get to trying to change the value once it is 'Filled.
I expected it to allow the field to be changed to 'Filled' and then show a validation error if I try to change it to something else.
I'm hoping someone can shed some light on this.