If a user plugs in a USB mouse and attempts to use it with Minecraft: Pocket Edition, they might not only face these issues, but the mouse might not even be recognized by the game in the first place and the game will not receive mouse clicks or mouse movement.

EDIT: While on a Galaxy S7 a mouse will popup and you are able to navigate with it, it is not using a built in game mouse. This causes certain parts of the UI to be completely unusable with the mouse.

Device: Samsung Galaxy S7 (SM-G930A)