Text box calculation vanishes

[MsDYJ]

I have an unbound text box in a mainform that totals calculations from 2
mainforms. The code I put in the control source works fine, but when I open
up the form the amount shows and then quickly disappears. I have the control
set to being visible but I don't know why it's doing that. Any suggestions?

Thanks

 

[MsDYJ]

Here's the code:
=[Forms]![frmProject]![sbfResources]![ResourceSum]+[Forms]![frmProject]![sbfMaterials]![MaterialsSum]

 

[John W. Vinson]

Here's the code:
=[Forms]![frmProject]![sbfResources]![ResourceSum]+[Forms]![frmProject]![sbfMaterials]![MaterialsSum]

Very hard to tell without seeing your code.

Might either of these controls be NULL? If so you'll get a NULL result. Try

=NZ([Forms]![frmProject]![sbfResources]![ResourceSum])+NZ([Forms]![frmProject]![sbfMaterials]![MaterialsSum])