I am trying to implement a diagram that will help my customers to set up various furniture in a building. To easy the work I am trying to use the floor plans as a background, so the user can easily place the shapes of furniture in the rooms. What i am doing now is to upload the image in the background of the document and set up layers for various shapes. But at some point i need to hide the document background so the user can see only the shapes he created.
Right now I don't know how to hide the background. I have tried with document.BackgroundStyle.FillStyle.Dispose() but it doesn't seem to do the trick, also document.BackgroundStyle.FillStyle.SetTransparencyPercent(100.0F) but this clears also the document background color.

What i really like to do is to assign the background image to a default layer and display that only when i need. It seems that this is not possible though since the background is scaling to the the area that have controls draw on it.

Any idea how to better implement this thing?