If the built-in GWT plugin doesn't work (properly), you can run/debug GWT in development mode as follows:
Either from the commandline, the Maven Projects view or from a run configuration.
2. Create a remote debugger configuration: go to Run configurations, click the green arrow and choose Remote. Leave every setting as is and make sure the host is localhost and the port is 8000.
gwt:debug outputs the following in the terminal:
[INFO] Listening for transport dt_socket at address: 8000
we can attach the debugger to it. This can be done by simply running the configuration created in step 2.
The code will now stop on breakpoints and you can debug etc.