Yes, essentially the same thing happens on my screen. At the top of the page, the magnifying glass in not visible. Realize too I am also using a touch screen. It varies. If I push the screen up, it can disappear, but pulling the screen back down a bit , it usually reappears. This forum has a sort of moving border at the top, and so some parts of the webpage do disappear, but by moving the screen around a bit, for me, I can usually get it to appear. Mind you, that's not a forum function (Search), which I will use very often.. I have limited need to search for threads or topics. If you want to keep track of threads you like, post a comment to it, and a reminder will pop up when ever it gets a reply or new post. And you can use those reminders for your forum bookmarks. ;-)
Tap the Black Star for a more advanced forum search.
My favorite Google search, is for Yahoo. Hahaha
RedHotPoker