There were some bug fixes released after CS6 came out. You should have the latest patch which is 12.03. Although it isn't always clear from the Help menu whether or not it is installed. So just click on Help > Updates. See below for details on what this contains.
Adobe - Dreamweaver Support Center : Updaters
When DW starts acting buggy, the 1st thing to try is clearing your Cache.
http://forums.adobe.com/thread/494811
If that doesn't help, try Restore Preferences
http://helpx.adobe.com/dreamweaver/kb/restore-preferences-dreamweaver-cs4-cs5.html
Nancy O.
