In the Video Effects (on the Toolbar along the bottom of the program), you'll find Auto Color and Auto Levels.
Although that flickering issue tends to be a problem whenever any Auto color/level effects are used. But it's worth a try.
Temporal smoothing remains in 13/13.1, at least in 13/13.1 Windows.
I am strictly an Elements Windows user, and there is temporal smoothing option associated with auto levels in Premiere Elements 11, 12, and 13/13.1 Windows 7, 8, and 8.1 64 bit.
Please see the following which specially answers that question
Quick summary....for Expert workspace
Lighting Panel expanded and its AutoLevels option
Then look to the Timeline video clip rubberband....right click Opacity in the Timeline clip's title bar, see Auto Level choice and its temporal smoothing option there. (Please refer to link for details).
Please let us know if this Premiere Elements 13/13.1 Windows opportunity is available to you on Premiere Elements 13/13.1 Mac.
Thank you very much !!!! This was the solution. Now I know the meaning of this yellow line. Sometimes Premiere Elements is not really self explaining and the manual also doesn't help.
But I'm happy that this forum helps !
The flickering is actually much better, but sometimes the auto levels still does strange colors. It changes between impressive appearance and cartoon feeling...
FWIW, if you want more detailed explanations of how to use all of the tools in Premiere Elements, you may want to check out my books on Amazon.