Nothing happens when i try to import terrain

Making new map, i import the terrain (which is 1081x1081 grayscale so it shows up red like it should) and set the settings. Click import, nothing happens. Box doesnt go away, terrain doesnt import. Set meters per pixel to 1 instead of 10 to see if that changed anything and nope.

Even weirder, i CAN import terrain images from existing maps?

Now i can't paint any textures despite those textures existing, and i can't add any???? (the + sign just does nothing). The old editor used to work, now we're stuck with this editor that can't even edit???