For real-time trending there's actually 2 options! Both can be found in the right click menu of the trend graph:

• "Show Most Detailed Data" will make it so you always see the most detailed data coming from the database, which in your case is real-time data. This is also a user setting, making it more permanent.
• Show Min/Max (can be found under the "Curves" sub item) will remove the min/max shading for your current trend graph. This will reset on each new trend graph you open though.