to click correct poin of stating frame of the sequence click ctrl key then press your mouse in the wanted sequence it will go to the first frame . if u want's to go end frame click ctrl + alt key then press mouse button in that sepuence it will go to the end frame.

You probably mean to state that holding CTRL while moving the blue bar through a sequence, it will snap to the starting from of any segment in the timeline. CTRL-ALT while moving the blue bar through a sequence will make it snap to the last frame of any segment in the timeline.

 yes