Question

The same thing is for all the buttons. Advanced theme.
I tired trying to figure out what is going on here.

Editor init:

   tinyMCE.init({
     // General options
    elements : "elm1",  mode : "textareas",
theme : "advanced",
force_br_newlines : true,
theme_advanced_buttons1 : "link,unlink,|,bold,italic,underline,strikethrough,|,justifyleft,justifycenter,justifyright,justifyfull,|",
theme_advanced_buttons2 : "",
theme_advanced_buttons3 : "",
theme_advanced_buttons4 : "",
theme_advanced_toolbar_location : "top",
theme_advanced_toolbar_align : "left",
theme_advanced_statusbar_location : "",
theme_advanced_resizing : true,
    });

UPD: TinyMCE works with simple theme. Problem caused by advanced theme only.

Answer 1

I was able to recreate your problem by deliberately introducing some errors in en.js.

So my suggestion is to have a fresh copy of en.js

Hope it helps!!