Symptoms
How to disable a tab in a view until to have all mandatory fields of the current tab filled?
Diagnoses
It's not possible to use the rule "Form passes validation" for this.
Resolution
If you need to make available/visible a tab (or other controls) according to the filling of other controls, we advise you to go through a "Data Label" which use and "Expression" as a value according to the mandatory fields 0 or 1).
Then, just create a rule on changing this DataLabel (On Change).
Here is a video that shows an example where I added a mandatory check.
