I have Premiere pro cc.
When I dragging sequence to another sequence's timeline- it doesn't became one unit, and all the videos and audios is still exist as they are.
I tried to change all the prefences and nothing working...
What can I do now?
You are doing what is called "Nesting".
In CC there is an Icon at the left end of the Timeline that will show your sequence nested or elemental.
thank you so much!!