When track changes are enabled, setting very large values for both the Top and Bottom values of Distance from text, causes an exception in ParagraphLayoutBox.

Stack trace:

{System.NullReferenceException: Object reference not set to an instance of an object. at Telerik.Windows.Documents.Layout.ParagraphLayoutBox.ArrangeOverride(SizeF finalSize) at Telerik.Windows.Documents.Layout.LayoutElement.ArrangeCore(RectangleF finalRect) at Telerik.Windows.Documents.Layout.LayoutElement.Arrange(RectangleF finalRect) at Telerik.Windows.Documents.Layout.SectionLayoutBox.ArrangeOverride(SizeF finalSize) at Telerik.Windows.Documents.Layout.LayoutElement.ArrangeCore(RectangleF finalRect) at Telerik.Windows.Documents.Layout.LayoutElement.Arrange(RectangleF finalRect) at Telerik.Windows.Documents.Layout.DocumentLayoutBox.ArrangeOverride(SizeF finalSize) at Telerik.Windows.Documents.Layout.LayoutElement.ArrangeCore(RectangleF finalRect) at Telerik.Windows.Documents.Layout.LayoutElement.Arrange(RectangleF finalRect) at Telerik.Windows.Documents.Model.RadDocument.Arrange(RectangleF arrangeRect) at Telerik.Windows.Documents.UI.DocumentPrintLayoutPresenter.MeasureOverride(Size availableSize) at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)} 

Steps to reproduce:
1. Enable track changes

2. Insert an image

3. Open Floating Blocks Layout Dialog

4. Choose Top and Bottom

5. Set "Distance from text" for both Top and Bottom to 2000px and click OK

Result: Exception is thrown

Additional info: Problem is also reproduced with very large images (1000 x 800 px) and small values for Distance from text.