5.0 M2/Eclipse 3.2 M07.
Debug a JSP. Set a breakpoint. When the breakpoint hits, you will never see source. The message displayed looks like:

Source not found for UserSetCriteriaControl.jsp line: 18

A tab pops up showing the current location as _jspService. As you step, the line number in the stack trace advances.

You can continue to step and examine variable state so debugging can still sort of work. Java breakpoints work as expected (source is displayed).

Right clicking and changing settings under "Show Source" have no effect. Both JSP and Default have the same non-effect.

What app server? What JDK version are you running Eclipse with and your app server wth?

FYI, I remember this had been working before I upgraded to M2. I can't confirm this though.

App server is Tomcat 5.5
JDK is 1.5_06

Hmm, try shutting down your app server, removing the deployment. Then restart MyEclipse using the -clean command line argument and then use Project > Clean and rebuild the project, then recreate the deployment. Now restart your app server and see if debugging works.

I have run with -clean
I have cleaned/rebuilt from scratch.
I have redeployed (from scratch) and restarted Tomcat.
I still cannot see source in the debugger. The line number message in the debug window reports that I am advancing through the JSP, but that is all I can see. I can send you a screenshot if that would help at all.

I have tried but cannot reproduce this problem locally, the only differences I can see between your setup and mine is that I am using Eclipse 3.2 GA and not the RC7 release and I am also using a new workspace. (Also you are using MyEclipse to do the deployment and not a custom Ant script correct?)

Let's try a new workspace to see if that helps:
File > Switch Workspace > C:\tempworkspace, hit OK

Now create a single new web project with a single default JSP in it. Setup the Tomcat 5.5 connector and deploy your project, set a break point on the line at the top of the template that computes the basePath and run the page from your browser. First, does the break point have a little check mark in it when you set the break point? And secondly, when you hit is, is the source shown?

This is no longer a problem in 5.0.1.

Glad it's working, thank you for following up.