Side marker light installation question

[frankdc]

Help! I seem to be missing something. I am trying to install the left corner light assembly and there is a fender tab that is not allowing me to push the light in flush. What am I doing wrong? Thanks

[SilverPhoenix]

Are you installing an aftermarket assembly? Some have fitment issues...

[frankdc]

Are you installing an aftermarket assembly? Some have fitment issues...

Yes but I have an OEM used one as well.

[Prospect62]

There's a little tab on the light that slides behind that tab you have pictured.