Expression right operand is null?

I imported a project from Vision 7.9 to vision 8.0.

I have a text field with the current non-editable background expression -

if({Root Container.CheckBox_Manual.selected},
	if({Root Container.NTF_Remaining Amt.floatValue}>=0, 

In designer when I run diagnostics on i, I see nonEditableBackground: Error_ExpressionEval("Expression right operand is null."). I just checked the 7.9.1 version of this project and the diagnostics on this expression are all good. What is wrong with this in 8.0? I know that {[client]colors/yellow} exists as a tag as well and is a valid path.

I had to go a few layers deep.

{Root Container.NTF_Remaining Amt.floatValue} referenced a calculation that was a subtraction where one of the bidnings referenced a sum on a table that had no rows, so a NULL value. I wrapped that binding with a IF and ISNULL, and things worked.

If you get the same error, just keep digging into the bindings layer by layer, you’ll eventually find something is null.