We want to change the settings of Rich HTML Editor (RTE) controls inside NewItem.aspx and EditItem.aspx pages (disable the ability to allowing user to change the font styles). NewItem.aspx and EditItem.aspx are the pages you see when you want to add/edit item in SharePoint list library.
If RTE control is put directly on the page then we can easily set its properties by setting the attributes of the control element. (for example we can do something like this <SharePointPublishingWebControl:RichHtmlField id='rteControl' AllowFonts='False'/>.
But what can we do if RTE control is part of ListFormWebPart?
1. Modify the .js files in 12hive. I would not recommend this approach, because changing OOTB files in 12hive could result unknown issues to the system.
To override functions, we can basically copy and paste the original functions from OOTB .js files to our pages. And change the functions implementation WITHOUT modify the signature of the functions.
RTE_ConvertTextAreaToRichEdit and RTE2_ResetAllToolBarStates are two most common functions you may have to change.