Not sure if anyone else ever comes across this issue ... But it seems after a certain point (not sure what that point is), maybe after spending more than an hour+ building and rebuilding a house ... I would have issues with some floor tiles, refusing to delete ... At first I would just log out the char, restart UO and it would work. Sorta like when you switch facets.shards, and see 'ghosts' of houses where they were ... and need to restart to get rid of them ... This all worked fine until yesterday it would not fix the issue, and I still could not delete about a dozen floor tiles. Couldn't even replace them with any other tiles ... Paging a GM was out of the question, so I randomly found a 'fix'. I would chose the eyedropper tool, and target a tile without anything on it (transparent blue floor in custom mode), this would give me the white marble floor tiles or something ... doing this made it possible to place the new tile on the stuck ones, and then delete those. Crazy workaround, but much less frustrating than leveling a design, cause 10 floor tiles refused to delete. If anyone else has this problem, I would suggest the eyedropper, transparent tile, replace and delete method (not official name).