The crop tool is on the command bar above the image, and the image ratio control is located at the bottom under the image. In order to pick the image ratio the cursor must be moved completely across the image.
Suggestion: the crop tool and its associated image ratio control should be available anywhere, for example by right-click.
I used to find this to be quite annoying too; as my main need was to change aspect ratio to “Unconstrained” … but then I found that I can hold down the Ctrl-key when moving one of the crop “handles”, and the aspect ratio will switch automatically to “Unconstrained”.
I often want to change the aspect ratio to a specific one, such as 1 : 1 or 16 : 9
(Barb Mac 11.7, PL6, FP6, VP3, Canon, Olympus)
I’m new here so I’ve been doing some experimenting. Hitting R brings up the crop tool without having to go across the image with the cursor - you probably already know, and I find the shift key lets me go unconstrained.