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How to fix TinyMCE browser issues

by hietpasd published Jun 19, 2012 08:55 AM, last modified Aug 16, 2016 10:50 AM
How to fix the many TinyMCE browser issues in Firefox 4+ and IE8+.

Internet Explorer 9 Fix

TinyMCE is not working at all?  The quickest fix is to enforce IE9 to be IE8.  If you do this make sure to do the next fix below for IE 8.


<meta content="IE=EmulateIE8" http-equiv="X-UA-Compatible"> 

into the <head> of your file

Make sure to remove any other meta tag which sets IE to a compatibility!  Look for tags similar to "IE-Edge".

Where to find main_template

The easiest way to find it is to go to 
ZMI > portal_skins > Find tab
and search for "main_template".  The one that is actively in use will be marked by an asterisk next to it.

Normally you can find it here:

(Plone Classic Theme) ZMI > portal_skins > plone_templates >


(Sunburst Theme) ZMI > portal_skins > sunburst_templates >

unless it's already been customized, in which case it will be in 

ZMI > portal_skins > custom


Internet Explorer 8 and Firefox 4+ Fix

TinyMCE is not working at all again?  This solves many of the issues in TinyMCE from improper loading, javascript errors, etc...  Follow these steps.

1. Go to ZMI > portal_java_script
2  First check "Development mode" on the top.  (We will need to purge the cache)
3. Find tiny_mce_init.js
4. Uncheck "Merging allowed?" and "Caching allowed?" checkboxes. (if not unchecked already)
5. Find tiny_mce.js
6. Uncheck "Merging allowed?" and "Caching allowed?" checkboxes. (if not unchecked already)
7. Go to bottom, click save.
8. Go to your webpage with the editor running, Ctrl+F5 for a refresh.
9. Go back to ZMI > portal_java_script
10. Uncheck "Development mode", go to bottom of screen click save.
11. Go back to your page, hopefully it will be working.

 Confirmed Fixes: Firefox 4+, IE8.


Firefox 11

Firefox 11 was released with a iframe bug.  Multiple TinyMCE windows on one page will not load correctly.  This is due to the bug in Firefox 11, not TinyMCE.  Firefox 12 resolved this problem, I recommend upgrading Firefox.