Copying multiple objects into a prim's inventory

Yesterday it worked. Today it doesn't. I can only drag one item at a time into a prim's contents list.

What happened?

This can be frustrating. It seems to matter what order you select your objects. For example, I've found when trying to fill vendor prims with a folder full of stuff, if I just select the folder and try to drag, it won't let me. But if I select the contents of the folder first, then select the folder itself, I can drag it into the prim. Sometimes I have to fool the prim by first dragging the contents of the folder onto the prim, but NOT dropping them into it, Then grabbing the folder and pulling it over.

This is what happens for me. I shift click on multiple items in my inventory and drag them into the contents tab of my prim. Only one item shows in my inventory. If I try to drag the items over again all of the original items show up and so do the duplicates. I end up with objects named something like 'Object' and 'Object 1'. Then I have to go and delete all the duplicate objects.

Sometimes if you close the edit window of your prim and then reopen it you will see all the objects.