Until now, in the editor, the background of a chosen tileset was also applied to the images of the terrain and object pieces on the panel at the bottom of the screen.
The newest version of the editor seems to have a slightly different approach to background selection again. When designing levels with very dark terrain pieces, like L2 Shadow, these pieces are incredibly hard to see now because the background in the menu at the bottom is black, even if a brighter background has been selected for the level itself. Thus, it becomes quite tedious to select the correct terrain piece.
Therefore, it would be nice if whatever background is selected for the level landscape itself could also be transferred to the images of the terrain and object pieces on the panel.
I haven't intentionally made any changes to this, but I'll look into it and see if I can figure out what broke.
Which version had the behaviour that you're expecting? I've tried in V1.20 and V1.23, and notice no difference between the two - and in particular, if I set a level's theme to L2 Shadow, I absolutely do get the lighter background color on the piece select panels.
So, I checked again, and in the latest version of the editor, having the proper background for the tiles panel works - at least when you select e.g. L2 Shadow as a level theme (like when creating a new Shadow level). Then the bottom menu with the tiles panel switches to it as well.
However, when you open an already existing level in the Shadow style that has the blue background, the background behind the pieces in the tiles menu at the bottom remains black, even when you switch back and forth between different tiles menus at the bottom.
The only way to reverse this is to change the level theme to a different one, and then back to Shadow. Then the backdrop at the bottom is also blue again.
As such, this is a really minor bug - but nevertheless, it seems like the tiles menu at the bottom should know what the current level theme is, also when you open a level using that theme as its primary one.
Yep, fair assessment. That shouldn't be too tricky to fix, either.
EDIT by WillLem: Pretty sure namida fixed this one as it isn't happening any more. The most likely commit is 3a3b567 as this includes a backgrounds-related updated and is labelled as a bugfix.