Only one issue – One touch Drawing Review

When I go to draw over a line, the lines don’t stay darkened so I have no idea what lines I’ve gone over and which ones I haven’t gone over. Other than that the game seems like a great game but it’s hard to play without knowing what lines you’ve crossed. I have iOS 11.2.5 on an IPhone 8. I had this same problem on my IPhone 7 with the same version iOS
Review by PersonWithAGoodTasteInGames on One touch Drawing.