The ability to filter lists of items (inventory, research, UFOpaedia) is incredibly useful on PC. This doesn't seem to be supported on Android, or if it is, it's not obvious how to bring up the filter textbox.
At first I thought maybe it was missing because I don't have a hardware keyboard to press the hotkey. I tried installing Hacker's Keyboard and forcing the soft keyboard to show up (from a notification widget), but that doesn't seem to work with this app.
Given there's no way to latch the middle mouse button outside Battlescape, this makes it very tedious to have to scroll through huge lists like UFOpaedia when all I want to do is check the stats of a weapon (in the inventory screen) or confirm I've already researched a corpse I'm thinking of selling. Filtering would improve both these use cases.
(Incidentally, some kind of little button on the screen to activate the filter would do wonders for discoverability on both Android and PC. A user who doesn't want the extra UI clutter could turn it off in advanced settings once they learn the hotkey.)