In the 60s, "uptight" meant "great," "fantastic," "excellent." This usage was popular among African Americans, particularly musicians. Refer to Stevie Wonder's "Baby, Everything is Alright, Uptight, Out of Sight."
Definitions include: Usually means automatically or concurrently complete one action without stopping the first action, i.e. on the fly online Help means that you don't have to stop using a software program in order to use the online Help.