What are the colors of the action timeline represent?

[Panha]

Hi there,
I have a long doubt of the colors in action timeline. When we create a new action, we get a red color in timeline. But sometimes, after making a some changes, then click ctrl + Z, the timeline changes to light blue. My question is, what are the different between the two colors in action timeline?

[Daxel]

The blue timeline means it's a smart action, so it's controlled by the rotation of a the bone that matches the name of the action. Red timeline means it's a normal action. Green timeline means it's a morph action (only has one keyframe).

[Panha]

The blue timeline means it's a smart action, so it's controlled by the rotation of a the bone that matches the name of the action. Red timeline means it's a normal action. Green timeline means it's a morph action (only has one keyframe).

Thank you.