Why does the formater crash if no text is selected in the editor and the cursor is on a blank line

Step 1 don't have any text selected and have not clicked anywhere in the content box yet.

Step 2 click the format dropdown

Step 3 Get the messagebox quoted below

[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) 
[nsIDOMNSHTMLDocument.execCommand]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  
location: "JS frame :: http://www.codeproject.com/script/htmlArea/htmlarea.js :: anonymous :: line 2798"  data: no]
by execCommand(formatblock);