Crop & Rotate Issue - Photos

I'm trying to create a slide-show of my holiday photos and wish to crop one or two photos.
But my Crop & Rotate function in Photos (Windows 10) seems to be playing up.
I want to crop the photo from the bottom up and NOWHERE else.
However, when I drag the 'white arrows' upwards from the bottom of the photo the sides also come in which I don't want.
There is also a grid view on the photo which never used to happen and I used to be able to crop a photo from the bottom or the top or the sides separately but now I can't crop one area of the photo without cropping another area, which, as I say, I don't want to do.
Please help - see screenshot.

Welcome to the forum.on the right the box keep aspect ratio is activated change that so it will let change ratio

But I don't want to change the ratio. I want the ratio to remain as it is, i.e. the original ratio. Why would I want to change it ?
I have noticed, however, that if I change the Aspect Ratio to 'Custom' this seems to have the desired outcome.

The AR is the ratio of height to width. By your own description, that is exactly what you do want to change.

Yeah, I think I see what you mean now. First reply by Samuria was unclear and ambiguous I thought.
Thanks, changed it to Custom and now it's working the way I want it to.