Hi Craig, I have a vague recollection that I saw this same behaviour on a VMware Horizon View VDI environment when the update for 'Crop and Center' was first released - but my memory fails me slightly!
Have you tested by installing the same client version on a thick machine that does not leverage any HDX optimisation, signing in with the same account, and testing that? If that's what you mean by 'web client' then I'll assume you've done that and it works fine (not sure what you mean by web client though?).
If indeed you see the option fine when not using an HDX paired client, I'd assume its a limitation of the way the HDX engine handles video communication (similar to how we're absent of gallery view capabilities in such an environment), although I admit I can't find anything specific to this in their documentation, and I suspect you'd have to ask Citrix directly.
Not an overly useful response I'm afraid, but like I definitely have something in my memory around a similar issue in a VMware environment!
