Error in backdrops in Flash SWF

[N64Mario]

Okay, say there is a backdrop object with the obstacle type labeled 'obstacle'. Then I have placed another backdrop object on TOP of that one. That obstacle type is labeled 'None'.
In the regular build, the player is able to walk across this obstacle that is above the other obstacle type labeled 'obstacle'.

However, in the SWF build, the player can NOT walk across this backdrop object labeled 'None' above the obstacle backdrop. So there must be an error somewhere here.

For example, I have a water title, or a mountain tile the player is supposed to stop to. In the frame view during programming, I add a road tile on top of the water title, or the mountain tile.
The player is able to walk on the road fine in other builds, but does not seem to be able to walk on the road over the water title in the SWF build. I even tried adding as backdrop object in events view, but it didn't work.

[Francois]

No error, it is explained in the docs. Flash treats backgroup collision in a different manner than MMF. Hte incovenient is that you cannot create "hole" in the background map

[N64Mario]

So I have to work around this? Ungh that means I'll have to rework the map a bit. I was really hoping there was a solution for this, but I guess not. Making a hole made things easy, and less backdrop objects. I really wish there was another solution for creating a hole that actually works in SWF like it does the other exports. :-/