Ok cool. I found out how to do it properly. 
		 * Max resize to height, set to null for double textarea height or -1 for unlimited
		 * @type {int}
		 */
		resizeMaxHeight: null,
		/**
		 * Max resize to width, set to null for double textarea width or -1 for unlimited
		 * @type {int}
		 */
		resizeMaxWidth: null,
		/**
		 * If resizing by height is enabled
		 * @type {Boolean}
		 */
		resizeHeight: true,
		/**
		 * If resizing by width is enabled
		 * @type {Boolean}
		 */
		resizeWidth: true,
Change to:
		 * Max resize to height, set to null for double textarea height or -1 for unlimited
		 * @type {int}
		 */
		resizeMaxHeight: -1,
		/**
		 * Max resize to width, set to null for double textarea width or -1 for unlimited
		 * @type {int}
		 */
		resizeMaxWidth: null,
		/**
		 * If resizing by height is enabled
		 * @type {Boolean}
		 */
		resizeHeight: true,
		/**
		 * If resizing by width is enabled
		 * @type {Boolean}
		 */
		resizeWidth: false,
That doesn't set a fixed min-height equal to default height, but does stabilise the width and allow unlimited max-height.