I committed a change to the JSONBuilder to stop using String.replace to do escaping of Strings. Very expensive to call this method, even if the target String doesn't contain any characters to be replaced.

I had to remove the generator code that was using attributesThatAreSet. Using the TabPane like this:
<ice:tabPane label="Second Pane of components" >
Here is some text in the second pane
</ice:tabPane>

Results in a tab with "null" as a label. It looks like the label field isn't being included in the set of attributes that are set in this case.

Still working on the renderers.

I've checked in some changes to LinkButtonRenderer and SliderRenderer to remove duplicate calls to property getters in the same scope and manually verified that none of the other renderers do this with any other property. We could possibly remove some constructions like "String" + "String2" + String3" and replace them with StringBuilder.append("String").append("String2").append("String3"), but from some decompilation I've seen the compiler does this anyway.