In Microsoft Word, the drag-and-drop functionality for Structured Document Tags (Content Controls) allows users to reposition an entire content control and all its contents within the document using the mouse.

What it does

When a user selects the boundary/frame of a content control rather than the text inside it:

• The entire content control is treated as a single unit.
• The control, including its metadata (tag, title, locking settings, data binding, etc.), moves to a new location.
• The content control remains a content control after the move.
• Nested controls move together with the parent control.
• Users can reorganize document sections without cutting and pasting.

Typical workflow

• Hover over a content control until its boundary becomes visible.
• Click the control's tag or border to select the whole control.
• Drag it to another location in the document.
• Release the mouse button to drop it at the new location.

Common use cases

• Reordering form sections.
• Rearranging template building blocks.
• Moving clauses in legal documents.
• Organizing repeating sections or structured content in reports.
• Reorganizing content that is bound to custom XML data.

Important limitations

The behavior may be restricted when:

• The content control is configured as "Content Control Cannot Be Deleted".
• The document is protected.
• The control resides in certain structures (for example, specific table layouts or protected regions).
• Editing restrictions are applied.

Word allows users to treat a content control as a movable document object, enabling the entire SDT and its contents to be repositioned via drag-and-drop while preserving the control's structure and properties.

HTML import fails when an image has an align tag set to a value different from center

<img align="top"
     width="170" height="61" />

When a DropDownList SDT form is saved in a XAML document and then imported with the XamlFormatProvider, an extra ListItem entry is added in the items collection of the DropDownList. The extra entry is the default "Choose an item".

To work this around, iterate all ComboBoxProperties and manually remove duplicates of the "Choose an item" entry.

var dropDownLists = radRichTextBox.Document.EnumerateChildrenOfType<SdtRangeStart>()
     .Where(x => x.SdtProperties is ComboBoxProperties)
     .Select(x => x.SdtProperties).OfType<ComboBoxProperties>();
 var defaultItemString = LocalizationManager.GetString("Documents_ContentControlsGenerator_ListItem");
 foreach (var item in dropDownLists)
 {
     if (item.Items.Count > 0 && item.Items.Any(x => x.Value != defaultItemString) && item.Items.Any(x => x.Value == defaultItemString))
     {
         var occurrence = item.Items.FirstOrDefault(x => x.Value == defaultItemString);
         while (occurrence != null)
         {
             item.Items.Remove(occurrence);
             occurrence = item.Items.FirstOrDefault(x => x.Value == defaultItemString);
         }
     }
 }

Add protection mode that allows to make the document readonly, but allow forms editing. In MS Word this can be enabled via the "Restrict Editing" menu. The option is called "Filling in forms" and protects the document, but leaves the Sdt elements (the forms) editable.

The line break symbol (Shift+Enter) is treated as a text character and it gets measured in the document position calculations executed when you click at the end of the document (somewhere after the line break symbol which ends the line). 

This causes two visual issues. The first one is that the caret goes after the line break symbol, which means that when ShowFormattingSymbols is False an empty space (non-existing in the document) is added at the end of the line. Even if ShowFormattingSymbols=true and the line break symbol gets display, it is not expected for ,the caret to get positioned after the symbol.

The second issues is that, when you start typing after you click at the end of the line, the caret position is corrected, but this leads to a jumps of the caret with one character to the left, which brings an unpleasant visual glitch.

To work this around, you can create a custom MouseSelectionHandler and override its RegisterDocumentMouseDown method. This will allow you to check if the caret is placed after the line break symbol and manually update the caret position if that is the case.

public class CustomMouseSelectionHandler : MouseSelectionHandler
{
    private IDocumentEditorPresenter presenter;
    private RadDocument document;

    public CustomMouseSelectionHandler(RadDocument document, IDocumentEditorPresenter presenter) 
        : base(document, presenter)
    {
        this.presenter = presenter;
        this.document = document;
    }      

    public override void RegisterDocumentMouseDown(bool ctrlPressed, bool shiftPressed, Point position, UIElement originalSource = null, SourceType source = SourceType.Mouse)
    {
        base.RegisterDocumentMouseDown(ctrlPressed, shiftPressed, position, originalSource, source);
        var box = this.document.CaretPosition.GetCurrentSpanBox();
        if (box != null && box.AssociatedSpan.Text == "¬")
        {
            document.CaretPosition.MoveToCurrentLineEnd();
        }
    }
}

 this.richTextBox.Loaded += (s, args) =>
 {
     var presenter = (DocumentPresenterBase)this.richTextBox.ActiveEditorPresenter;
     presenter.MouseSelectionHandler = new CustomMouseSelectionHandler(this.richTextBox.Document, presenter);
 };

ArgumentException occurs when using the voice typing feature of Windows (started with the Windows Key + H key combo) to convert speech to text in RadRichTextBox.

Exception stacktrace:

System.ArgumentException: 'Requested distance is outside the content of the associated document.'PresentationFramework.dll!System.Windows.Documents.TextPointer.TextPointer(System.Windows.Documents.TextContainer textContainer, int offset, System.Windows.Documents.LogicalDirection direction)
  PresentationFramework.dll!System.Windows.Documents.TextContainer.CreatePointerAtOffset(int offset, System.Windows.Documents.LogicalDirection direction) 
  PresentationFramework.dll!System.Windows.Documents.TextParentUndoUnit.Do() 
  PresentationFramework.dll!MS.Internal.Documents.UndoManager.Redo(int count) 
  PresentationFramework.dll!System.Windows.Documents.TextStore.RedoQuietly(int count)  PresentationFramework.dll!System.Windows.Documents.TextStore.SetFinalDocumentState(MS.Internal.Documents.UndoManager undoManager, System.Collections.Stack imeChangeStack, int appChangeCount, int imeSelectionAnchorOffset, int imeSelectionMovingOffset, int appSelectionAnchorOffset, int appSelectionMovingOffset)  PresentationFramework.dll!System.Windows.Documents.TextStore.HandleCompositionEvents(int previousUndoCount)  PresentationFramework.dll!System.Windows.Documents.TextStore.GrantLockWorker(MS.Win32.UnsafeNativeMethods.LockFlags flags)   PresentationFramework.dll!System.Windows.Documents.TextStore.RequestLock(MS.Win32.UnsafeNativeMethods.LockFlags flags, out int hrSession)