This is not a Seam-problem, but a Rich
feature. Read the documentation of the ajax-submit very cerafully, because without proper configuration ajax will submit every submitable item on your page.
Wrap blocks in a4j:region and set all appropiate attribues on the a4j.support. Things like limitToList, eventQueue, timing aspects etc. should be carefully configured. If you have different
taskson your page, give each one its own form.