I am trying to set up some navigation on my form using command buttons - but I am running into problems

I have set up a command button at the top of my form with the initial programing in the "on entry" tab
if @update goto elementname
In theory i belive this should take me to the element which it does in a way, (the cursor appears in the element)
However to get to the element I need to "page down" since the screen does not "move".
So
I included a PgDn command in the programming - so that it read
if @update goto elementname
PgDn
That didn't work either

- still no screen movement
I then added a forceredraw() command to the programing so that it now reads
if @update goto elementname
PgDn
forceredraw()
That did'nt work either

I also tried using throwfocus(elementname) - with the same results.
the target element is on a tabbed page - i don't know if this has any effect on the programing
- can anyone enlighten me ?
Many thanks in advance