In preview text lines window, add small indicator that there is more text not shown

But there is already one:

Ah, I hadn't noticed it before. It's rather subtle. I'm a new user and read the entire online help, but didn't see any mention of this "more text not shown" icon. I suggest  mentioning this in the online help in the "Previewing and Reading Notes" section.

Yes, I agree that it's subtle. But it is so to avoid creating visual noise. Please also notice that these icons change when you scroll the text using Left-Right buttons (or with Left Click + Scroll). 

Thanks for pointing out that this is not described in help. Of course it should be there, I'll add the description of this behavior.

Added more detailed description to help