Number of lines to display option is not selectable

[regular_user]

Hello, I'd like to change the option "Number of lines to display above/below found text" but it's greyed out and not selectable. I'm sure there is something I'm overlooking, but why is it greyed out? I have the free version of the software, could it be a paid feature? I don't see any notifications about that, though.

[DigitalVolcano]

I think that feature is only available in the Pro version. You're right though- it's not mentioned in the manual.