Mouse over doesn't show gas in mesh tiles in Oxygen Not Included Posted December 7, 2018 Can also confirm on Windows SU-291640. it's not only true for gases but also for liquids. The single-click contents-of-tile pop-up list of blocks, one per substance, is the one that's missing the gas or liquid. On first click the amber highlight-border shows the mesh tile. On second click the highlight disappears; since there's no block, there's no place to put the highlight.