Want to make your misspelled words stand out a ‘bit more when composing a message in Firefox?  It is easy to do with this quick about:config tweak.  You can select no highlighting, a dotted line, long dots, a single straight line, a double underline or the default squiggly line.

Here is how you can make your spelling mistakes stand out more in Firefox.

1. Enter About:config in the Firefox address bar. If it pops up an alert, tell it that you know what you’re doing and proceed.
2. Search for ui.SpellCheckerUnderlineStyle. If you find anything, skip to step 5.
3. If your system is like mine, you found nothing. That means you have to add this configuration value. Right-click the main portion of the window and select New > Integer.
4. Now, enter ui.SpellCheckerUnderlineStyle to create a setting by this name.
5. Now you can set the value of this setting to one of several options: 0 for no highlighting, 1 for a dotted line, 2 for long dots, 3 for a single straight line, 4 for a double underline (like you see above – that’s my pick), and 5 for a squiggly line, which is the default.

Once you are done, you will be able to spell check like no other!  Well, ok – that might be a little dramatic, but you will have a more customized misspelled word notification.

Thanks goes to Download Squad for this amazing find!

How do you use it?  That much is simple:

1. Click the "Add Proofreader" link on your link bar to add a Proofread button above each text box.
2. Click to find spelling mistakes, misused words, and grammar errors
3. Click to continue editing.

Right now the bookmarklet does have a few limitations, such as it is limited to 7,000 characters worth of text, and it only works in text area form elements, however this is a great way to bring a great tool with you, no matter what web site you are on.

You can pick up the After the Deadline bookmarklet on AftertheDeadline.com.

The first step to take would be to bookmark this link (or drag and drop it onto your bookmarks toolbar).

+ spell check

When the bookmarklet is clicked, Firefox will turn on the built in spellchecker and highlight any misspelled words that are on the page you are currently browsing.  You can check for suggested changes too, of course they will not be saved to the page though.  This quick bookmarklet does come in might handy though for anybody who spends their time proof reading any online content.

(Kudos to Download Squad and UrbanoAlvarez.es!)

For some reason though, by default Firefox does not do spell checking in all text areas. You can fix that for youself like I did with a little about:config tweaking.

In your about:config (type about:config in the address bar to access) search for this string:

layout.spellcheckDefault

Change the value from 1 to 2 to get spell checking for all text fields and not just the big text area boxes.

+ Learn More About Switching Your Dictionaries in Firefox!