I am running SharePoint 2010. I have a list with several Lookup columns. One of the Lookup columns if called 'Air Card'. I would like to create a InfoPath that disables the control for 'Air Card' if it contains data. If it is empty then I want the control to be enabled.
And this is where my problem starts. I created a rule as the one displayed in the screenshot below hoping that the field would be disabled if it contains data. if it does not then it would be enabled. This is the function I try to accomplish but now everytime try to add or edit the list item the control is disabled. I tried several other for the confition like 'matches pattern' etc but none of them keep to be working.
If the trick is that the field is a Lookup field ?