C4C Key User Rule Editor - I cannot create a new rule

Hi,

I have created an extension field in a master layout.

It is an indicator field. I want the indicator to be switched on, in case a certain field is filled with a value. The extension field is to be used in another scenario.

For switching on this indicator I want to set up a rule.

So as usual I go to the adaption mode - master lay out - select the extension field and press edit.

When I click on the rule option o pop up appears for adding a rule. I do not have a [create] option.

Where do I create new rules? Do I need to activate something somewhere in the current UI first?

Kr.

MJ