With two levels same elevation - which both have textured/coloured floors, it seems the 'lower' texture shines through in the 2D plan and takes precedence in the 3D plan (if added later). Is that intended? ok

In the layer logic, it's not intented and should be fixed in Beta 7. I also changed the JNLP file to avoid some "delayed" updates that I experienced and that could explain why you thought that the Beta 6 didn't fix the bug in the furniture table.

mazoola, sorry, I don't want to spend too much time on managing Beta differences. Java Web Start is surely not perfect on this point, but it's much easier for me to manage.

I'm sorry to see the 'visible and invisible objects in group' feature I was so happy to find in Beta2 disappear in more recent versions. I like being able to group together a large batch of light sources and fine tune them without having to ungroup them first [...]

I removed this feature, because I didn't want to wonder whether the size and position of a group should be updated when one of its item is made invisible, moreover because it's possible to resize the group itself. Imagine the following scenario: you group 3 pieces of furniture and make one invisible in the group. Then, should the size and position of the group should be the size of the visible pieces only? What should happen to the invisible piece if the user resize the group? Not easy to answer, if you want a consistent behavior...
But your case is interesting and I wonder if I should go back or not. To prevent the problem I explained, I could for example forbid to resize a group with partially visible pieces. But how the beginners could guess when the group is resizable or not? [:-/]

About your wall heights issue, I don't think there was some recent changes on this subject recently. The height of wall at a given level is actually the height given in its dialog box + the thickness of the level, if that level is not the lowest one.