Unable to drag keyframe to end or beginning of clip

This is so strange. Wondering if anyone else has experienced this behavior.

It happens with regularity when I'm working on creating a slideshow music video. I'll add the ending keyframe I want, then I'll drag it to the end or beginning of the clip. But it stops short and will not let me drag all of the way.

Sometimes if I zoom in close, then it will let me drag it the rest of the way, or if I turn off snapping, that will sometimes allow it. But other times, it doesn't matter what I do - it won't let me drag it all of the way to the end. So, I have to extend the clip further out, then drag the keyframe to the point I want it at, then contract the clip back down again to that keyframe point so that it is now positioned at the end.

Watch this video to see what I mean:

You should know what the frame is. It's just a image.

I don't understand your response. What does the fact that it's an image have to do with the ability to drag the keyframes to the end of the clip length?

I know this is like a year later, but I'm having this exact same problem. Did you ever figure this out?