When I add another page without letting redline appear during the edit process, I can have a clean page without redlines. I prepared the same pages without redlines now by starting over.
I'm not sure what exactly you did to cause this to happen but I cannot reproduce. Can you be more specific? It seems you did more than just add a page. Perhaps you used a certain key combination? Copied pasted something? Created blocks?
I uploaded some pictures to the media folders on Composr, and then I used those pictures in comcode boxes and put some links to some other pages.
I have been playing on the same page (editing, deleting and adding some new lines using "red line") yet, I wasn't able to reproduce the error, either.
I'm closing this as v10 has entered long-term maintenance status, and this is not a critical bug. Feel free to open a new tracker issue if you upgrade / use v11 and find this bug on v11 as well.
(Click to enlarge)
I have been playing on the same page (editing, deleting and adding some new lines using "red line") yet, I wasn't able to reproduce the error, either.