I don't know if this helps you, but the TOTAL time (ie. the total duration of the now playing list) is displayed in two places:
1)
If you have the 'now playing' node loaded into the main panel, the total time, file size and number of files is displayed in the bottom right hand corner of the main panel.
2)
If you have the now playing list loaded into one of the side panels, then the total time is displayed on the right in the 'header bar', across from where it says 'now playing'.