08-12-2011 5:21 PM, EDT
I can't make formatting changes!
It's likely you're suffering from HTML Code Buildup, which results from having formatted, reformatted, and formatted again over time (and often the result of pasting in text from another source or re-using an old campaign multiple times). With the text still highlighted, click the unformat icon in the toolbar, located at the bottom of the tool bar next to the HTML button. This will remove all of your text's formatting and allow you to apply a fresh coat using the toolbar.
If you're pasting in content from an outside program, it's best to start by pasting your text into a plaintext program like TextEdit or Notepad before pasting into your campaign. This will ensure that your content is clean text so you can format easily within the campaign.
HTML formatting from outside programs should not be pasted into the editor. If you're creating HTML content in an outside program, you'll want to use a blank Upload Your Own HTML template instead.