For what it's worth -
That method works perfectly fine for placing an object in a level and populating it with items.
I found however if you add items to a template and you place that template in the GM pallette for GM mode those items do NOT appear when the object is placed in GM mode. They only appear when you pre-place the object into the level in the editor.
So if I put eight mugs of beer into a barrel template and call it a "kegger" the kegger will have those mugs if I place it in my level, but if I just add it to the barrels in the GM pallette and fire up a campaign when I drag and drop my "kegger" from the GM items pallette then it will be empty.
I dunno if that is a bug or not. I guess it's working as intended, but it would be beneficial if this was supported to allow mods with custom pre-populated containers for GMs. The "workaround" of course is to use customized treasure tables for the containers, but that's all a bit fiddly for something that would be more easily done through the items picker I think.
(yeah I know, I know it's the philosophy of "change the root not the local"... it's just everything in the editor requires way more steps than it should
)
