add this to functions.php
JavaScript:
//src - https://gist.github.com/thierrypigot/7fe4b3e40735d4b9a3ca
<?php
/* Hook to init */
add_action( 'init', 'tp_editor_background_color' );
/**
* Add TinyMCE Button
*/
function tp_editor_background_color()
{
/* Add the button/option in second row */
add_filter( 'mce_buttons_2', 'tp_editor_background_color_button', 1, 2 ); // 2nd row
}
/**
* Modify 2nd Row in TinyMCE and Add Background Color After Text Color Option
*/
function tp_editor_background_color_button( $buttons, $id )
{
/* Only add this for content editor, you can remove this line to activate in all editor instance */
if ( 'content' != $id )
return $buttons;
/* Add the button/option after 4th item */
array_splice( $buttons, 4, 0, 'backcolor' );
return $buttons;
}