-It's helpful to have a model of how styling works. Any piece of text can have its
-style changed, but there also two global notions of style. The control's {\it basic} style
-is the fundamental style for the whole control, to which other character and paragraph styles are
-applied. For example, you can change the control's overall font by either calling SetBasicStyle with
-the appropriate font style, or by calling SetFont.
-
-The {\it default} style, on the other hand, is applied to subsequently inserted
-content. You might click on a Bold formatting tool, which sets bold as one of the default
-attributes, and typing will appear in bold. Then when you select Italic, both
-bold and italic attributes are applied as you type. The default attribute
-is set with \helpref{SetDefaultStyle}{wxrichtextctrlsetdefaultstyle}.
+\subsubsection{wxRichTextCtrl and styles}
+
+Styling attributes are represented by one of three classes: \helpref{wxTextAttr}{wxtextattr}, \helpref{wxTextAttrEx}{wxtextattrex} and \helpref{wxRichTextAttr}{wxrichtextattr}.
+wxTextAttr is shared across all controls that are derived from wxTextCtrl and
+can store basic character and paragraph attributes. wxTextAttrEx derives
+from wxTextAttr and adds some further attributes that are only supported
+by wxRichTextCtrl. Finally, wxRichTextAttr is a more efficient version
+of wxTextAttrEx that doesn't use a wxFont object and can be used to
+query styles more quickly. wxTextAttrEx and wxRichTextAttr are largely
+interchangeable and have suitable conversion operators between them.
+
+When setting a style, the flags of the attribute object determine which
+attributes are applied. When querying a style, the passed flags are ignored
+except (optionally) to determine whether attributes should be retrieved from
+character content or from the paragraph object.
+
+wxRichTextCtrl takes a layered approach to styles, so that different parts of
+the content may be responsible for contributing different attributes to the final
+style you see on the screen.
+
+There are four main notions of style within a control:
+
+\begin{enumerate}\itemsep=0pt
+\item {\bf Basic style:} the fundamental style of a control, onto which any other
+styles are layered. It provides default attributes, and changing the basic style
+may immediately change the look of the content depending on what other styles
+the content uses. Calling wxRichTextCtrl::SetFont changes the font for the basic style.
+The basic style is set with \helpref{wxRichTextCtrl::SetBasicStyle}{wxrichtextctrlsetbasicstyle}.
+\item {\bf Paragraph style:} each paragraph has attributes that are set independently
+from other paragraphs and independently from the content within the paragraph.
+Normally, these attributes are paragraph-related, such as alignment and indentation,
+but it is possible to set character attributes too.
+The paragraph style can be set independently of its content by passing wxRICHTEXT\_SETSTYLE\_PARAGRAPHS\_ONLY
+to \helpref{wxRichTextCtrl::SetStyleEx}{wxrichtextctrlsetstyleex}.
+\item {\bf Character style:} characters within each paragraph can have attributes.
+A single character, or a run of characters, can have a particular set of attributes.
+The character style can be with \helpref{wxRichTextCtrl::SetStyle}{wxrichtextctrlsetstyle} or
+\helpref{wxRichTextCtrl::SetStyleEx}{wxrichtextctrlsetstyleex}.
+\item {\bf Default style:} this is the `current' style that determines the
+style of content that is subsequently typed, pasted or programmatically inserted.
+The default style is set with \helpref{wxRichTextCtrl::SetDefaultStyle}{wxrichtextctrlsetdefaultstyle}.
+\end{enumerate}
+
+What you see on the screen is the dynamically {\it combined} style, found by merging
+the first three of the above style types (the fourth is only a guide for future content
+insertion and therefore does not affect the currently displayed content).
+
+To make all this more concrete, here are examples of where you might set these different
+styles:
+
+\begin{enumerate}\itemsep=0pt
+\item You might set the {\bf basic style} to have a Times Roman font in 12 point,
+left-aligned, with two millimetres of spacing after each paragraph.
+\item You might set the {\bf paragraph style} (for one particular paragraph) to
+be centred.
+\item You might set the {\bf character style} of one particular word to bold.
+\item You might set the {\bf default style} to be underlined, for subsequent
+inserted text.
+\end{enumerate}
+
+Naturally you can do any of these things either using your own UI, or programmatically.
+
+The basic wxTextCtrl doesn't make the same distinctions as wxRichTextCtrl regarding
+attribute storage. So we need finer control when setting and retrieving
+attributes. \helpref{wxRichTextCtrl::SetStyleEx}{wxrichtextctrlsetstyleex} takes a {\it flags} parameter:
+
+\begin{itemize}\itemsep=0pt
+\item wxRICHTEXT\_SETSTYLE\_OPTIMIZE specifies that the style should be changed only if
+the combined attributes are different from the attributes for the current object. This is important when
+applying styling that has been edited by the user, because he has just edited the {\it combined} (visible)
+style, and wxRichTextCtrl wants to leave unchanged attributes associated with their original objects
+instead of applying them to both paragraph and content objects.
+\item wxRICHTEXT\_SETSTYLE\_PARAGRAPHS\_ONLY specifies that only paragraph objects within the given range
+should take on the attributes.
+\item wxRICHTEXT\_SETSTYLE\_CHARACTERS\_ONLY specifies that only content objects (text or images) within the given range
+should take on the attributes.
+\item wxRICHTEXT\_SETSTYLE\_WITH\_UNDO specifies that the operation should be undoable.
+\end{itemize}
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