THx for answers, both would work, but i have another problem. The thing i wanted to have in those hiding/unhiding rows are pictures, and i don't know how to do this, pic is allways just floating on top, either the cells are hiden, resized or whatever.

Any thoughts about this? The think i need is click - picture vissible between a1 and a2(or a3) click-hidden. I need to have "picture link" in every row and i want to dispplay them on click or double click as many as i want - so placing picture in comment wont work, cause only 1 will be vissible at a time.