I mean from Material/Map Browser to Material Editor. Drag or double-clicking, so it appears in the material Editor slot.
For example, this wood material you see there looks good now. But sometimes it imports with the wrong Color Space and it's too bright.
Another thing is for new materials, I save to the Material/Map Browser. 3ds max tends to regenerate the preview from tim to time. When I have certain scenes open, it generates a preview with wrong color space. But after restart, in another scene, it looks right. Hard to explain...