I've been using Dreamweaver a lot at work over the last few weeks for the Prototyping portion of a project elaboration phase. I've been astounded at how often it simply gets confused to all hell and needs to be restarted in order for it to sort itself out. It happens with a number of operations - copying/pasting table cells/rows will often corrupt the display, adding and then deleting extra white space will often leave table cells displayed too large on the screen (but the backend code is fine), new files are often undetected by when you copy them into your site directory (although not always, sometimes it gets them), and finally sometimes you'll rename library items and the assets view won't update to reflect that.
In each of these cases, reloading Dreamweaver returns things to normal. I'm not sure whats weirder - the fact that it does this, or the fact that I just accept having to restart the thing 4-5 times in a session without really thinking much about it!