Thanks for bringing this to our attention.  It's a problem I would love to get to the bottom of, but the first step is to recreate locally.  LogViewPlus is memory intensive, but in the next few months we will be revisiting this.  I suspect the rewrite will address this issue if we are not able to resolve it before then.  I will let you know when a beta release is available.

I can see where the line idea is helpful for chat applications, but I am not sure it would help with log files.  It is often not clear which messages have been 'read'.  LogViewPlus will tail log files and some applications can produce a lot of data.  So just because a message was displayed doesn't mean it was seen.

I think the closest thing we have to this feature is the "Clear Entries" command (F4).  This will clear all log entries from the view.  All log entries displayed after this action will therefore be new.

Hope that helps,

Toby