A dissolve transition requires that you set a background and key transition rate for the auto transition. A fader transition does not use the transition rate.
Click Navigation Menu > Live Assist > MEs and select the ME that you want to perform the transition on.
Click Trans > Dissolve, or press DISS in the Transition area on
the control panel.
Tip:
Click one of the Transition Rate buttons to quickly select the rate for the transition.