I always have caching at the the forefront of my thoughts, I have tried recycling the app pool, restarting the web site, clearing browser cache, using the DNN clear cache and restart site tools - but to no avail. The width/height was one of the items I was trying t change, but others such as changing the skin and removing a few of the tools will not take effect, even though the configuration is saved with these values.

Interesting to note that when switching from DotNetNuke.RadEditorProvider to TelerikEditorProvider this message displays, but doesn't display the other way around:

RadEditorProvider is not default html editor provider now, any changes will not apply to current editor provider. If you want to make configuration take effect please update default provider to 'DotNetNuke.RadEditorProvider' in left drop down list.

Not being able to save happened to me the first time I tried to change settings. Then I realized that I had to select the "everyone" branch of the tree on the left instead of the default. That fixed it.

Has to be a bug - or is it? It seems that once you change the provider to be the DNN Editor and configure it there is no going back. This is the message I keep seeing over and over while the Telerik Editor is listed as my provider:

RadEditorProvider is not default html editor provider now, any changes will not apply to current editor provider. If you want to make configuration take effect please update default provider to 'DotNetNuke.RadEditorProvider' in left drop down list.