In the Martix/Component Items Tab, you can choose the "Add Items" button and select to add an existing item. The problem is the item is added to the matrix without any information in the Dimension 1 field and you can't update that field. How can you create a matrix for existing items, with out recreating them from scratch? Recreating them looses all previous sales information. We did this frequently in 1.3 in cases where a non matrix item is now being offered in more than 1 size and now should be matrixed.
Thanks,
TomT