There are two ways I deal with this. The quickest is usually to double-click on the timeline clip I want to change and make the edits in the PiP/Title Designer. Usually all the other content is visible and I can make the changes while seeing all the other items on the screen.

The other way is to lock the tracks of all content below the item you want to edit which prevents them from being selected in the preview window:

Quote There are two ways I deal with this. The quickest is usually to double-click on the timeline clip I want to change and make the edits in the PiP/Title Designer. Usually all the other content is visible and I can make the changes while seeing all the other items on the screen.

The other way is to lock the tracks of all content below the item you want to edit which prevents them from being selected in the preview window:

Thanks optodata.

The locking of the tracks is pretty smart, didn't think of it! (although not very practical if you have to edit several tracks all the time).
Making the edits from the pip/title designer is, I guess, the way to go. I just avoid it most of the time because it takes a few seconds to load. It's weird because sometimes I end up selecting the right track from the preview window, but I don't know how I do it, it's like "it just happens after you try several times".

I wonder if Cyberlink addressed this "issue" in versions 18, 19 or 365?

Quote I wonder if Cyberlink addressed this "issue" in versions 18, 19 or 365?

They made some changes and it sometimes works well but there can be snags, like this discussion shows.

Maybe a submission to Rate Us & Provide Suggestions (under PD's File menu) to use a combination of Alt/Shift/Ctrl keys when clicking on the preview screen to cycle through the layers would help. I just submitted that myself!