Give texture bug?

Maybe it's supposed to be this way, I don't know. Here goes:

I've created a simple box with: llAllowInventoryDrop(TRUE);
When I drop landmarks and notes on it, it works fine
When I drop textures on it, it sets the texture on the side which I drop on
As creator it seems impossible to drop a texture inside the box (unless in edit mode)

Now I login with another avatar

When I drop landmarks and notes on it, it works fine
When I drop textures on it, it denies me to do so, shows a locked pad lock
Now, this is interesting, if I create a folder and put my texture in it, then drag the folder to the box, then it accepts the texture and saves it inside.

Eh? Is it supposed to be this way?

Also tried this outside owned land but same behaviour.

Shouldn't textures just be added to box when dragging them onto it? Even if I'm the owner? And I'm not currently editing the object.

Please advise, not a big issue but seems a little strange to me.

From the (a) wiki: "To drop an inventory item onto/into an object, hold the Control key while dragging any inventory item onto the object (the object you're about to drop your item onto will be highlighted with a red frame)."