What does yellow circle in the contents navigator mean

I am trying to keep my contents navigator as clean and organized as possible. I have a few contianers in a WebPage that I want to put in a Containers folder. When I do that the container name gets a rectangular border and a yellow background. When I select the container a large Yellow circle is displayed next to tthe container name.

What does that mean? Is there a definitive document that explains these types of things in the IDE. It would be nice if the circle had a help tip assigned that says what it means when you hover over it.

John

It shows the scope of the elements in the navigator. Red is for private, yellow for public, green for global.

OK thanks. I had earlier figured out that a red circle meant private but had not yet encountered yellow or green. So I got confused , when the yellow, which was not previously displayed, suddently showed up when I put the element into a folder.