Samsung UE40ES7000U E-Manual page 39

Lock a channel so that the channel
cannot be selected and viewed.
N
This function is available only when
the
●
Rename channels
(Appears only if you have selected an
analogue channel.)
Lets you assign a name of up to five
characters to an analogue channel. For
example, Food, Golf, etc. This makes it
easier to find and select the channel.
Channel Lock is set to On.