How to disable automatic brightness setting on LG monitors?

I have two LG monitors (both 23MB35PM) which have an annoying and distracting feature of automatically changing their brightness at random times, probably due to some power saving mechanism.

How can I switch it off?

Solution 1:

The option is not in the main menu, but has a dedicated button here:

Click the button enough times to select OFF.

Solution 2:

I have the LG 24m45 and I was having the same issue. I looked all over for the menu to change it, however it is actually in a special menu-which is an awful idea. I found the separate menu by pressing down the function(FUNC./) key twice and the menu popped up. Hop this fixes your problem!