When trying to set and ymax item to a graph, it kept telling me "Warning. Field [ymax_itemid] is not integer".

After some debugging time, i found the values assigned by the popup to the parent window are wrong (ymax_itemid=>"<item_description>", ymax_name=>"").
I found the JS function addValues does not assign values correctly due to the tmpStorage variable not being reinitialized in the loop, which triggers the bug when parentDocumentForms.length is (always) wrong.

The attached small patch fixes the problem.