Are you getting any JS errors in the console? It’s possible if you have a conflict it can cause other scripts to stop. Also are you running any plugins that add to the TinyMCE editor?

yes im getting this

Uncaught TypeError: Cannot read property ‘length’ of undefined 

im using plaintext

thanks

Can you provide here, or PM a link to your forum? If locked can you include login details in the PM.

also, are these users using a specific browser?

Well taking a look yes it does look like you have an error, although It’s hard to see where exactly it comes from. The only problem I can see is jQuery is v1.11.0, and I believe we are now on v1.11.1, so something is loading an older version. Only thing I can suggest is disabling plugins and see if the error is gone. If the error disappears, then enable one plugin at a time until you get it back, then you know whats causing the problem..

If that doesn’t work, then it’s possible it’s coming from the WP theme itself. Try setting a default WP theme again to see if you can get rid of the error.

Why it’s happening to some and not others though I can’t explain. As Mr Papa says, try and find out what browsers these users having problems are running

i tryed the default theme and the problem is gone… so i guess i have to check the theme yes? 

Yes unfortunately that is probably the next step, really out of our hands I’m afraid although if you do have any questions we will always try our best to assist. Short of that you would probably have to speak to the theme developers to see if it’s something they can resolve.