The problem can be reproduced on the track changes demo at https://demos.telerik.com/aspnet-ajax/editor/examples/trackchanges/defaultcs.aspx 1. Copy a list from word (Bullet or numbered doesn't matter, but numbered is more problematic) 2. Paste into the content area with track changes turned on 3. Apply Bold, Underline or Italics to the pasted list Result: The list seems to break itself into 3 separate lists all spaced further apart than initially. Numbered lists will go from 1,2,3 to having 1,1,1.