Can only type in pages and posts as html code

I use the Custom Communuity theme by Themekraft version 1.15

Suddenly I am finding that I am only able to edit or add new pages or posts in html mode and not the text mode. There used to be two boxes at the top right hand side of the posts/pages where you could switch between the two but these are now gone.

Anyone have any ideas as to what has happened or how I get the text mode function back again??

Thanks Helen