What is the comparing keyword used in the sentence: Both birds and cats can be pets to people?
Word to the wise: This won't work if the textarea is hidden when the tinyMCE initialization script runs. (By "hidden," I mean the textarea or one of its ancestors is set to "display: none.") When initializing, tinyMCE measures the height of the textarea onscreen, then replaces it with an iframe and gives the iframe the same height via an inline style ("height: 300px").
If your textarea is, for example, located inside a modal window that is set to "display: none" when you initialize the editor, tinyMCE will measure the textarea's height as zero and won't assign an inline height to the iframe. –