Stadium: 6-5-3 does not melt into the ground [won't fix]

[TMarc]

When using mixmapping feature, the block 6-5-3 is the only block that does not remove the ground polygons and does not melt into the ground.
The main reason is probably because it is a junction block between grass and dirt.



It is the middle block here:


Here placed on the ground next to each other, and using 6-1-1 for junctions:


Before you say "it is in the wrong direction", when using Mixmapping, the dirt is not removed and "replaced by grass" either (I tried this before posting).

Besides this, apparently it cannot be placed at all on top of dirt hills.
Please also add possibilty to add grass on dirt top, this could be nice
quick sketch without road blocks:

[angry_duck]

Unfortunately this will not be fixed.

Here is the technical reason (for expert mappers!):

In classic block mode, when you try to place a block on ground, it will be refused if the ground is not compatible with the block. Most ground blocks in stadium are compatible with flat grass and flat dirt, but are not compatible with water nor the transitions from grass to water (blue edges of the pools) or from grass to dirt (grids between grass and dirt surfaces).
In mixmap mode, you can place your ground block on any type of ground, but the ground polygons will be removed only if it is one of those "compatible grounds" (because we know that in this case the edge of the block will fit perfectly with surrounding blocks).
Your block (6-5-3) is compatible only with a transition from grass to dirt (in classic block mode, it can be placed only on the grids that separate dirt and grass). So if you place it on flat grass or flat dirt, the polygons will not disappear (and if the editor removed them, you would get little ugly holes on the edges of the block).

[TMarc]

Thanks a lot for the very detailed answer, I already feared and thought of something like this, but it's not dramatical.
There is still block 6-5-1, and the possibilty not to use blockmixing for 6-5-3 luckily.