An OrgVue Paste Oddity
If you have prepared an empty dataset (no nodes) but which has calculated properties in it, then before pasting in data you will need to create a dummy node in the dataset before you paste the new data in. This dummy node can be deleted once the paste is complete.
If you do not add the dummy node then when you paste the data in, the operation will remove properties that do not exist in the source data, even if you choose Merge Data. This is because the operation is presuming that the empty dataset is to be replaced by the content of the incoming data.