According to the (conflicting) documentation of TinyMCE, the editor takes on the size of the textarea (or other) element that it replaces. It also says that you can set the
I am facing the same problem but I end up doing this
#tinymce-textarea_ifr { min-height: 500px !important; } .mce-tinymce { width: 96% !important; margin: 0 auto !important; }