No it isnt, and like someone else who mentioned this recently,and like has been suggested before,I do not know why they dont tell you this before you sign up, of course its possible that they do,and its not seen or not read.
Edit, after rereading your post.
Well at least I dont think so.
You cannot transfer a mobile account to the webbrowser or vice versa , the rest someone else will tell you as I only use the browser format.
Chrome and or Firefox, mostly they are fine.
I havent had problems with full screen for while,its the kind of thing that can happen with updates to the game , but not always, the full screen icon should be visible at the top of the page,others have mentioned problems like this before, you my have to adjust your screen size.
If all else fails try the admin team.