Heya. There's a new version of the editor! Here: https://forum.dune2k.com/topic/28587-map-and-mission-editor-v14-release-candidate-full-of-improvements-and-new-features/
Not sure if it fixed the fullscreen image stuttering issue. I've seen it too. Usually I keep a movie or something up on the side while I edit, so I'm typically working in windowed mode. Anyway, there are several different tilesets with image data, and the tileset with those sand-sunken structures would be BLOXBASE, if I remember correctly. The 'tileset options' are in the top bar, here: https://prnt.sc/ritrkf
Hope that helps.