It adds the keys from the master version as well. In 8.4 we added some more keys to CUVc in the master version so your 2 extra keys brought it over the limit of 80. I have increased the limit to 200. This will be available in 8.4 2017-09-13.
Hello!
You can mark it as closed as option. If document is connected with other documents you can not delete it so you will not be able to delete PO, as you will not be able to remove Goods receipt...
