Can anybody tell me how to updating a single-select picklist string field to null?

 

This portion of my application is an html view with three embedded forms and one embedded view

When the Chart Search Form is submitted, the record is saved in Zoho and the html view is refreshed with a session paramater which causes the Chart Search form to reload for Add.    [There isn't anyway to get it to reload for edit and have it look good and everything else work too...been there. tried that.]

 

So in the Add: on-load script:

I fetch the saved record Chart_search and populate the fields.

 

Then in the Add-Validate script - I fetch the record again and update it.  So if the user went back to "-Select-" for the Price Bracket field I need to set Chart_Search.Price_Brackets (which is a string picklist that had been set to (e.g.) "$100,000 to $300,000") back to null.

 

         I've tried

                      Chart_Search.Price_Brackets == null;

                      Chart_Search.Price_Brackets == "";

                      Chart_Search.Price_Brackets == "-Select-";

                      Chart_Search.Price_Brackets == "empty string field".removeAllAlphaNumeric()

 

While the on validate script runs fine, when the refresh of the html view and it trys to repopulate the chart_search form (in Add: on-load script) with this value, it is flagged as an invalid entry.

 

I cannot get it returned to null no matter what I do.  It keeps showing up as an "Invalid Entry" and reverts to the previous value 

 

[and how does it know what the previous value was if it did the update in the validate script?  And knows it is an invalid entry?  Has to be left over in the user interface from before the refresh].  

 

HELP!