Checkout: cForms Conflict
If you are using the cForms plugin and the WordPress Shopping Cart plugin on the same site, chances are that your TinyMCE visual editor in WordPress will be broken when you try to send newsletters, edit templates, etc.
Cause of problem
Solution to the problem
In your WordPress dashboard, under cForms > Global Settings > WP Editor Button Support, there is a checkbox where you can tick “Fix TinyMCE error” which will solve the problem.