User blog comment:Sarah Manley/Updates to the Editor Redesign/@comment-1091639-20110628065847/@comment-3388044-20110705110202

The ability for users to untick Enable Rich Text Editor on the Editing tab at Special:Preferences has to be maintained. The new Oasis editor is still doing some of the unintended, unilateral editing of prior edits that the old Oasis RTE was doing. This does not happen when one is able to untick Enable Rich Text Editor on the Editing tab at Special:Preferences, and use only Source mode. (Of course, this does not prevent those users who leave it ticked from having the editor perform unintended, unilateral editing of prior edits, despite having edited only in Source mode: We can’t control other people’s edits with the untick, only our own.)

I believe what happens is that, when in Visual mode, and one presses the Increase indent button, instead of a series of colons (i.e., “ : ”) being input, HTML formatting using  tags is entered. Then, when the button is pressed, these HTML tags are converted to colons. However, the editor also impacts previous,  , and   tags. (Simple example.) In those instances where, for example, it strips  tags from a block of text indented by one or more colons, it can have the effect of concatenating the text. In those other instances, where it adds line breaks around  tags, in a block of text indented by one or more colons, it has the effect of returning the rest of that block of text to the left margin, thereby destroying the indent.

Without the ability for users to untick Enable Rich Text Editor on the Editing tab at Special:Preferences this will occur constantly. Why? Well, all those users who normally untick that box, even though they will be editing in Source mode, will still effect these inadvertent, unilateral edits. Thanks!