Double upload causes http ahah error if the maximum file size exeeds the sum size

If you dont select a file and first click "add another file", you are able to select more than one file before uploading. If both (or more) files are in sum bigger than the maximum file size, we get an http error when selecting "save" or add another file. I suggest, you shouldn't enable to add another file row while no file is selected or catch up that http error.

Greetings from Ger,
Daniel