@caleje,

Right now hovering over the word in the browser will show the popup, and clicking on an open popup will add the word to your private wordlist. On touchscreen devices, tapping a word once will pull-up the popup, and tapping on it again will add the word to your private wordlist.

I agree that the "close tooltip" button should either work in iOS or we should get rid of it. I'll see what I can do.