How you debug toolkit programs? Please give meinformation for this…
For the client-side check out Firebug. IT Mill Toolkit has extensions for it and it is an excellent tool for debugging / developing JavaScript / DOM / CSS.
For the server-side we do not directly provide debugging tools. Well, there exists logging features in Toolkit, but I think you are referring more to IDE area? Eclipse with various plugins (e.g. Tomcat Sysdeo plugin) is good for setting up brakepoints etc.
You can use any debugger built into an IDE. I myselft prefer to use Eclipse together with Sysdeo Tomcat Plugin. This allows to do hot code replacements - you can just set a breakpoint into your program, edit some code on running program and continue running.
See this tutorial for setup of those tools:
So the debugging looks something like this: