UIOBJECT FontString

Behavior change in 4.1
Prior to Patch 4.1, :GetWidth and :GetHeight would sometimes return the region size and sometimes the actual size of the text, depending on which :Sets you had previously used.

Now, :GetWidth and :GetHeight always return the size of the region - as automatically computed or as set by you (via SetWidth/SetHeight or via multiple SetPoints)

To get the width of the string prior to wrapping, use :GetStringWidth. To get the width after wrapping (because the region was too small), use :GetWrappedWidth