Returns or sets the mark used to show formatting changes while change tracking is enabled. Can be one of the following WdRevisedPropertiesMark constants: wdRevisedPropertiesMarkBold, wdRevisedPropertiesMarkDoubleUnderline, wdRevisedPropertiesMarkItalic, wdRevisedPropertiesMarkNone, or wdRevisedPropertiesMarkUnderline. Read/write Long.