Based on the preliminary feedback for 455, we'll be reverting some changes in 456:
* the instance editor will once again show all instances, with the exception of those whose only change is a modified (nudged) pixel-offset.
* the map editor will swap click/ctrl+click again, although we may have to come up with a failsafe to prevent too much turf redundancy (maybe a way of visually indicating when there are multiple turfs on a tile)
* the map will distinguish between out-of-bounds and NONE tiles (that was an oversight, not intentional).
There are also a few bugs in the isometric layout that will be fixed. We'll look into a few of the minor feature requests but most likely those will not be addressed until a future release (in the interest of stabilizing the beta).
FYI, 455 was re-released (as 455.1047) due to a corrupted sound dll. If you are experiencing sound-related crashes in the beta, redownload.