[187.209] Static grids don't merge
A player sent me a world that had issues with airtightness. The issue turned out to be that a portion of the ceiling of the station was a separate grid (see attached thumb.jpg).
I cleaned up the world leaving only the station, the ceiling part and its attaching asteroid.
I recolored the separate grid pink so it can be obvious, see attached zip file.
Once you load the attached world try to merge those grids together. I've tried simply placing more blocks to unite them and even merge blocks, neither worked.
You can look at the entity list to see if they're still 2 grids.