Thanks for your advise,

i was so sick of it that i threw the whole thing away and started from scratch.
I have a little question.....

If i make a calculated field, that field will fill the database ?, cause thats is what it must do.....

anyway the thing is working better already.....

but i find it strange that the behaviour only existed on the first row...
if i moved from row one to row two and had the amount field changed nothing happend, moving back to row one would calculate everything ok...

its weird, and certeinly undesired behavior.