Not a Rigol user myself but as I understand it, data collected (the amount of it, I mean) would be the same every time, the sole difference being where inside a certain window time, the triggering parameter would be shown.
In other words, you can decide where on your screen you want to see the trigger thing.
One interesting thing about digital oscilloscopes is that you can see what occurred before the trigger (backward time travel ). This is possible because the scope is continually taking and storing the data and all the trigger does is determine what portion of that stored data will be displayed.
Thus there is a horizontal position trigger adjust as well as a vertical position adjust.