public variable doesn't change?!?

[crptcblade]

on my form load, i set a dimmed variable to the value of a public variable on another form:

Private Sub Form_Load()
   newSize = frmMain.prefList(1)
End Sub

Then I change the value of newSize, and when I unload the form, I set the public variable to the value of the dimmed value:

Private Sub Form_Unload()
   frmMain.prefList(1) = newSize
End Sub

but when I open the form back up, the value of frmMain.prefList(1) is unchanged, an idea why that could be??