I am sure Firefox 4.0.1 is intended to have a working spell checker by default.

iirc firefox changed the spellchecker used by default, and it should have been improved, but I am on firefox5 myself at present, and that did not have a working spell checker until I added a dictionary add-on.

To make sure your spellchecker is turned on use

• Firefox button -> Options |options| advanced|General|
  Browsing [x] - check my spelling ...
• you may need to enable add-ons if you are using them

I am using an en-GB edition of firefox 4, so even if I looked at my 4.0.1 it may not be the same as yours.

• Which language is your firefox en-US ?
• Do you have any dictionary or spell check add-ons, and if so
  • are they enabled or not ?
  • what are they ?
    Use Firefox Button -> Add-ons
    (or in Windows it is keyboard Ctrl + Shift + A

Note also that the spell checker only works on multi line firelds, so it will work in say an email message or this forum, but not when typing in a web address in the location bar.

It is easy to downgrade to Firefox 3.6, but that may have disadvantages, one of which being that it may not be supported for too long now that there are rapid release cycles of Firefox versions.

• see installing a previous version of firefox

I checked & the box was checked to check my spelling , & my English Australian Dictionary add on cant be enabled, only choice I have is to remove it.

where can I find out if firefox 4.0.1 has an in built dictionary.

thanks john

The Australian spell checker makes a point of using spellings such as British favoUrite, you could use the British English dictionary, that does work in Firefox 4.0.1 and 6.0a

The Australian spell checker dictionarry suggests disabling version checking for Betas etc using other add-ons (also see http://kb.mozillazine.org/Updating_extensions ). Disabling checking may not be recommended. Some of the other suggestions in that article may also help, such as looking for other mirrors or modifications of the add-on.

As the add-on developer suggests a contribution be made better support may be expected, but the support site listed is merely the Firefox KB article: using the spell checker

Mis-spellings are being highlighted (underlined) but right-mouse click is not offering me the spell options but only the usual browser menu of Back, reload etc EXCEPT on this forum. Is this a compatibility problem?

The forum where I have the problem is powered by Simple Machines LLP

Susan,

Remember the spell check only works on fields allowing multiple lines, and therefore not on all sites/paged.

If you continue to have this problem I suggest you start a new thread, and in your question state the URL's of sites that do, and do not work.

Thanks, downloaded English dictionary & now works OK.

Thanks for the response but the forum I post to regularly is multiple lines. I can type 1000 word reply if I want. Spell check always worked there until the upgrade.

I will contact the web master of the forum to see if he can help before starting a new topic.

Did you check in the right-click context menu of the text area if Check Spelling is check-marked?