Update...

 

If I change the UseDNNDefaultWidth="true" setting to false within web.config, the HTML and Preview modes do not shrink. 

 

However, what happens now is that the CEHtmlEditor window expands beyond the border of the skin (using the DNN default skins). 

 

 

When the setting is false, the source code width=762px and height=700

 

762 is too wide for my use.  Where is CE getting this setting from and how do I set it?