The select button will not work on the remote for my brand new samsung q70 LED tv. This is also the case when I use the Smart Things app on my phone. Every single other button works fine and I still get the red indicator showing that a signal's being sent to the TV when I click the select button but it does nothing.
If it also doesn't work using SmartThings remote app then your remote is ok. I would first pull the plug on the TV for 5 mins, and if that doesn't work do a full reset of the TV.