Modify “editXslt.aspx” xsltVisualize function as follow
Change UmbEditor._editor.selection() to UmbEditor._editor.getSelection();
FYI: You can find “editXslt.aspx” under “umbraco/developer/Xslt” folder
Solution for Umbraco CMS Preview issue
This is an issue with Umbraco 4.7.1 and It’s been fixed but only in the latest nightly builds of umbraco.