When I change a ui.xml file (e.g. change css styles), these changes don't show up in the application. The only way to get the changes visible is in Eclipse to choose Project-> Clean ... and to remove and recompile the whole project.
My settings:
-noserver -remoteUI "${gwt_remote_ui_server_port}:${unique_id}" -logLevel INFO -war "${workspace_loc:NewComApp/war}" -codeServerPort 9998 com.myapp.MyApp

My tomcat (alhtough I understand that this does not influence the superdevmode):

Anyone experiencing the same problem. This makes iterations during development very slow, because compiling the whole project because of some minor changes to the layout seems ridiculous.
The ui.xml files are located in the same package as the java source files:
Any advice on this?
After a lot of research and a little help from a friend I want to describe the solution. First of all you need to understand that SuperDevMode (like DevMode) translates what it finds on the classpath of the JVM where the SuperDevMode runs.
So for the solution in Eclipse it is necessary to point the classpath to the source directory.
For this you need to open the config dialog of your SuperDevMode:
For 2. You need to open "Java Build Path" select "Order and Export" your Project Properties in Eclipse.
After that you you just hit F5 in eclipse to see any changes (ui.xml or java code) instantly compiled by SuperDevMode compiler instead of Eclipse Project Build compiler
Along with a tomcat installation this lots of time.