thank you Doru, the thing is the max width is not based on number of elements but their size in pixel so we can't predict what will be the elements (and so the biggest element height) in the next line so, as a reversed align top, I put the elements from the bottom right corner to the top left. (Just put the elements in the reverse order) The last line is the fist one and less filled. But there is certainly a simple trick to fix this. What about the extra step to move at the end ?