Go to the Preferences (under Edit on the PC version) and uncheck the box for Show all Do Not Show Messages.
If I do not want to see those Videomerge message again, unchecking the Show All Do Not Show Messages in Preferences does not work for me.
What has for a short period of time is
when I get the message
I put a check mark next to "Do not show again" and the click on No.
If I want the message and it is not showing up as expected (that is, program is not detecting a solid color background), then I go to preferences to put a check mark next to Show All Do Not Show Messages option.
Often I find this feature an unpredictable feature.
Didn't Bev say that she'd already selected the option to "never ask me again"?
This is why I suggested unchecking that preference first.
I checked the box "yes" to answer the question "Do you want to apply videomerge to all clips" and never ask me again. Now it shows up EVERYTIME. How can I get the effect off without having to manually delete it each time?
The combo that worked for me was "Do not Show Again" and "No", not "Do not Show Again" and "Yes"
I never use Videomerge. Chroma Key is the way to go when and if needed (and if you are a Premiere Elements Windows user). I have not looked at the reliability of "Do Not Show Again" - "Yes" combo with or without the preference set, only the "Do Not Show Again" - "No" combo.
If bev really needs "Yes" instead of "No" in that type of message, I think better served with Chroma Key rather than having to try to undo an automatically mis-done Videomerge which can also be done on an on demand basis if really wanted.