There are occasions on Forms when a Data Lookup Control is used to select a value by a user but the relevance of the Control or the value selected becomes nullified by virtue of actions (changing conditions) involving other controls on the form. However, there is no option to clear or delete the selected value from the Data Lookup control in the Forms Rules settings. The option exists to manipulate the value of controls such as Text boxes and one would expect to be able to at least delete the selected content on Data Lookup controls as well. Being unable to do so on Data Lookup controls becomes problematic particularly when the Data Lookup control is bound to a column on a Sharepoint list and the values are fed through to the underlying column when they shouldn't be. Being able to manipulate the control on the form through Form Rules would be the most "ergonomic" method.
Thank you very much for posting your feedback for our review. At this time, we will not be adding this request to the near-term backlog, as we are focused on other highly requested features. However, we reevaluate requests every quarter and will reach out if priorities change. Please keep the feedback coming as it is critical for our longer-term planning.