Some buttons do or do not respond when using the remote control.

IMPORTANT: This article only applies to specific products. Please check the Applicable Products of this article.

For other remote control issue, refer to TV remote control not operating properly or not responding at all.

The remote control of these TVs basically uses Bluetooth communication, so you can change channels or volume without pointing to TV. 
However there are some cases to use infrared communication on remote such as turning on TV. 
In this case, you need to point remote control to TV.