We've introduced a whole new page setup dialog for you in 2011, volume 1! To get there, click the button on the bottom of the Page Setup section:

which will give you:


and

You can configure a huge list of things! Margins, orientation, paper size, which can be configured for the whole document, or by section, as well as options for sections, headers, and footers of your document.
There's also a new columns dialog, reachable by clicking the "more columns" option under "Columns" in the Page Setup section:

Again, columns can be configured by section, or for the whole document.
We also now support line-numbering documents from the UI! Simply choose from the line numbers drop down, and voila!

All of these features are still available at run time, too, from the DevExpress.XtraRichEdit.API.Native namespace. For example, to set up three columns (like our example):
// Specify a measurement unit
richEditControl1.Document.Unit = DocumentUnit.Inch;
// Get the first section in a document
Section sectionDoc = richEditControl1.Document.Sections[0];
// Create columns and apply them to the document
SectionColumnCollection sectionColumnsLayout =
sectionDoc.Columns.CreateUniformColumns(sectionDoc.Page, 0.2f, 3);
sectionDoc.Columns.SetColumns(sectionColumnsLayout);
Check out the full list of supported properties:
Page Setup:
ShowPageSetupFormCommand
Section.Margins
SectionMargins
Section.Page
SectionPage
SectionPage.Landscape
SectionPage.PaperKind
SectionPage.Width
SectionPage.Height
Section.StartType
Document.DifferentOddAndEvenPages
Section.DifferentFirstPage
Columns Setup:
ShowColumnsSetupFormCommand
Section.Columns
SectionColumns
SectionColumn
Line Numbering:
ShowLineNumberingFormCommand
Section.LineNumbering
SectionLineNumbering
SectionLineNumbering.Start
SectionLineNumbering.CountBy
SectionLineNumbering.Distance
SectionLineNumbering.RestartType
For more information, see the following samples:
How to: Configure the Page Layout Programmatically
How to: Create a Three-Column Layout with Uniform Columns
Demo Module: Line Numbering