Object border size keeps changing

Hi, I'm trying to add effects to my clips, but this problem is getting in my way

Whenever I work on a clip in fusion, the border size changes from clip to clip.

I actually want the border size to be changed for certain clips, but I can't figure out how to change it.

For your information, I have uploaded two screen shots that show the dfferent sizes. As you can see, the size seems to vary from clip to clip, even thought the clips are the exact same size.

A related problem - I've got one clip adjusted really well, biut I don't know how I did it!

It's good because the blur effect is visible beyound the left and right of the image and is cropped on the top and bottom - the way I want all my clips. This is shown on the third screen shot. If anyone can tell me how the effect was done, I would be grateful.

HOW DO I ADJUST THE SIZE OF THE BORDER?

Thanks!

Musicailty