Two ideas: (1) I think you might have some extra room to the left of the fuses-tab to make it double as wide, so you're able to show six or more tiles at once, instead of just three. (2) by making the fuses-tab a little longer at the bottom, you're able to put the scroll-buttons inside of the tab, instead of under it. That might improve the visibilty of the buttons, especially if you make a pop-up prompt explaining that there can be multiple tabs now in the first level that has them, so people know where to look from then on.