I'm afraid your problem lies somewhere else, as both CKEditor demo (that is running version 3.5.3) and the samples from the 3.5.3 installation package work correctly.
If the demo works correctly in your browser, try the samples and compare them with your own code to check what is wrong.
Thanks for reporting the problem. Can you create a new ticket on the CKEditor Development site to let the developers investigate it?
Make sure to read the Bug Reporting Instructions and Ticket Specs articles beforehand in order to make it easier for the developers to examine the issue. Please describe the environment where the error occurs and provide detailed steps to reproduce it. The more info you give, the easier it will be to track it. Thanks!
That looks like a problem with your user-agent string.
What does it says for the User-Agent if you type "about:support" in the url bar? For example this is the correct User-Agent for Firefox 4 on Mac: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
Re: CKEditor (3.5.3) not working at all in Firefox 4 (FF4)
I'm afraid your problem lies somewhere else, as both CKEditor demo (that is running version 3.5.3) and the samples from the 3.5.3 installation package work correctly.
If the demo works correctly in your browser, try the samples and compare them with your own code to check what is wrong.
Documentation Manager, CKSource
See CKEditor 5 docs, CKEditor 4 docs, CKEditor 3 docs, CKFinder 3 docs, CKFinder 2 docs for help.
Visit the new CKEditor SDK for samples showcasing editor features to try out and download!
Re: CKEditor (3.5.3) not working at all in Firefox 4 (FF4)
Your browser is not compatible with CKEditor.
CKEditor is compatible with Firefox 2.0 or higher. It is also compatible with Internet Explorer 6.0+, Opera 9.5+ and Safari 3.0+.
However, that is Firefox 4 installed on Windows 2008 Server R2, so maybe the issue lies there.
It does work on Firefox 4 on a Windows 7 installation.
Thank you.
Re: CKEditor (3.5.3) not working at all in Firefox 4 (FF4)
Thanks for reporting the problem. Can you create a new ticket on the CKEditor Development site to let the developers investigate it?
Make sure to read the Bug Reporting Instructions and Ticket Specs articles beforehand in order to make it easier for the developers to examine the issue. Please describe the environment where the error occurs and provide detailed steps to reproduce it. The more info you give, the easier it will be to track it. Thanks!
Documentation Manager, CKSource
See CKEditor 5 docs, CKEditor 4 docs, CKEditor 3 docs, CKFinder 3 docs, CKFinder 2 docs for help.
Visit the new CKEditor SDK for samples showcasing editor features to try out and download!
Re: CKEditor (3.5.3) not working at all in Firefox 4 (FF4)
What does it says for the User-Agent if you type "about:support" in the url bar?
For example this is the correct User-Agent for Firefox 4 on Mac:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0.1) Gecko/20100101 Firefox/4.0.1