Video transition is smaller in one side

[GabrielPugas]

Hello.

I'm trying to add a video transition between two clips, but the transition gets smaller in one of the clips. How can I fix this?

And why I can't add effects when the end of the clip has a little triangle at corner?

[Ann Bens]

The triangle means end of the clip.

If you want the transition in the middel you need to trim back the clip.