Well, I guess there was only one thing that you could do...
Ding a ding dang your dang a long ling long?
3) point at (it works like a mouse) the "input" app and click
Use the other remote that came with the TV, not the mouse remote. I have 10 LG TV's from that era at work, they all came with a standard remote with number buttons, vol + -, channel + -, input, etc and the stupid mouse remote that we never use.
Waste not, get your budget cut next year.