Samsung Galaxy Note 3 — What does color of circle in icon of Widgets 'Active apps manager' mean?

What does color of circle in icon of Widgets 'Active apps manager' mean?

As we know, on our Samsung Galaxy Note 3, there is a Widgets named with 'Active apps manager'. Its icon is a circle with a digital char in it. The digital char might stand for number of current active apps.

I found that sometimes the color of this circle is green while sometimes it becomes green and yellow, even sometimes it becomes red.

I wonder what the color means.
Thank you in advance.

The screenshot is as below.

James_Watson

The screenshot is as below.

![image][1]

[1]: https://fscl01.fonpit.de/userfiles/6936538/image/ActiveApps-1442660670312.jpg

I wonder why the text and circle became red while the number is zero.

I think that the number 0 maybe stands for the number of active apps. So, if there is NOT any active app, why the icon becomes red?