How can I add "Underline" to the text entry box tools?

[firemcd (Daniel McDonald)]

Cannot find a way to add “underline” as an option in the text editor box.
I searched for existing topics, but they all involved removing undeline from links.
Thank You!

[craiger522]

I usually switch to the Text tab in the Text Editor and insert inline css to achieve an underline. Like this:

<span style="text-decoration: underline;">THE TEXT YOU WANT TO UNDERLINE</span>

[Jamie]

WordPress removed it and justify in 4.7.1 so we followed suit. You’d need code or a plugin to add the button back in. However, the keyboard shortcut remains in tact.

Code to put in child theme functions.php

function bb_tiny_mce_buttons_underline( $buttons_array ){
		
	if ( !in_array( 'underline', $buttons_array ) ){
		$insert = array('underline');
		$inserted= array_splice( $buttons_array, 3, 0, $insert ); // splice in at position 3
	}	
	
	return $buttons_array;
	
}

add_filter( 'mce_buttons', 'bb_tiny_mce_buttons_underline', 9999 );	

Plugin:
Install TinyMCE Advanced and you can then add in Underline (and other things) back into TinyMCE.