I figured this out.
For those that might be confused:
Use the FORMULA BUILDER in the create/edit rules interface to create a simple test that should produce a boolean output. e.g IsNull([something])=TRUE or Nz([something])=TRUE depending on datatype
Then if the bool is TRUE the action you identify in the action section will happen.
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joe vandervest
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While I also search out work arounds like you have done here, I still feel like this is an issue. We should not be forced to create new fields and workarounds to do something basic that the form should be capable of doing on its own. Especially since the old forms allowed this more easily.
Let's take steps forward not backwards!
Joe, I have a similar issue on the "new" forms that's frustrating the hell out of me. I have the exact formula you have listed above using IsNull: IsNull([Related Deployment])=TRUE
What I'm attempting to do is hide a section of the form if the related field is not set. This formula is still not yielding the result I want.
Screenshot of rule attached.
