This may just repeat what someone else has already said, but I did find (on my iPhone) that by going to Appstore/Updates; then the button Purchased and then My purchases, you see the list of all the apps you have bought or accessed, and you can then delete or reload any of those apps. This worked to eliminate the last, most troublesome, of my "shaded-waiting" apps. I must say Apple is remiss in not addressing the problem, given that this thread of confusion and complaint has been around since 2012.