Every once in a while your phone checks if the pen is still there I guess? A really must have feature thanks for asking though just turned it off
Quite possible that you're right. The S-Pen detection is a feature that keeps the digitiser active even when the s-pen is stored in it's tube. This is why it uses a bit of battery.
Why you might not want to disable it - if you have another s-pen then it doesn't work when the box is ticked. so if you also have another Note series phone or tablet then you can't use the same s-pen for each.
I have the Bluetooth S-Pen (HM5100) and it just doesn't work when the box is ticked.
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