I've run into this a few times now so I decided to go ahead and make a post about it.
On the platform tile set maps supply crates placed near other objects sometimes makes them inaccessible. In every case where this has happened to me the crate cannot be opened. I can click on it, but the create doesn't open and the supplies never appear.
Here is a screen shot illustrating a situation where this happened. Even after destroying the objects next to the supply crate it was not accessible. Maybe it is because the teleporter is next to it, but in any case either the behavior of the crates when clicked or the placement of these crates should be modified. I have never had this happen on maps that use the other tile sets.