"Coloring" option in the IDE

[SPH]

Hi,
I don't know what I did, but the IDE is behaving strangely for the first time:
I have a multi-page code snippet, and when I double-click on (for example) "debug", all the "debug" instructions turn green. I already knew that. Now, if I click on (for example) "plot", all the "plot" instructions turn green, but the preceding "debug" instruction remains green!

What did I do to cause this? (It's a very useful feature that I'd like to replicate whenever I want...)

Thanks!

[AZJIO]

Marker?

[SPH]

Marker?
How does it work?
Which function key?

[SPH]

Ah, okay, I checked the link.

Could we have this function natively in PB ?