I know that, in a bar chart, I can display an expression solely as a pop-up on hover / mouseover by unclicking the visual display options, and only leaving 'text as pop-up' checked. I can't figure out how to do the same for a mekko, as the visual options are checked and grayed out as default for all expressions, meaning that I can't uncheck the visual representations and leave an expression as a pop-up only.
