Isnull or null question in formula

[sonar1]

I'm using the following
IF ToText ({EComp.EmDateEnd} ) = "" or Isnull({EComp.EmDateEnd} ) - I have used this statement before - now all the sudden EmdateEnd - which appears to be null is not processing properly - any thoughts.
I've tried every variation I can think of.

 

[kelley80209]

Did you try putting the IsNull expression first in the comparison....

IF Isnull({EComp.EmDateEnd}) or ToText ({EComp.EmDateEnd} ) = "" ?

I have read that this seems to make a difference.