long feedback steps and trouble, there are many times suddenly appear connection problems, you have to refresh the page, and then you will find screenshots saved uploaded attachments and pictures disappeared;
when I label a PDF, there will be several situations where the PDF page is always on and out, but the PDF content does not appear, and the second is: display error, modification cannot be saved to the document (how big a PDF will appear cannot be labeled, ( Add a PDF greater than a certain MB can not be labeled why not in the help or prompt inside the instructions, my PDF size is 60M