Perform the changes in interactionBlock, noting any change in selection
and possibly a change in the size of the paragraph (ar 9/22/2001 - added for TextPrintIts)
a slight kludge so subclasses can have a bit more control over whether the paragraph really
gets released. important for GeeMail since the selection needs to be accessible even if the
hand is outside me
A change has taken place in my paragraph, as a result of editing and I must be updated. If a line break causes recomposition of the current paragraph, or it the selection has entered a different paragraph, then the current editor will be released, and must be reinstalled with the resulting new paragraph, while retaining any editor state, such as selection, undo state, and current typing emphasis.