what is this red area on section line?

[aryastark]

valarhello,
i copied these elevation lines from main to module. it appears half tone red area on the section tool line.
do you know what is that red area trying to tell?

[Podolsky · Accepted solution]

I think this is source marker highlight. You can show or hide it on plan (but it's not going to print it).
To hide to you can use command View / On Screen View Options / Highlight Source Marker
Also try command View / On Screen View Options / Marker Range

To change colours (i.e. yellowish) go to Options / Work Environment / On Screen Options