This window displays the current return stack. Each line in this window represents a different level on the stack. The base level being 'Main Program'. It is continuously refreshed as the program executes in the debugger.
A new feature of the workbench is the ability to change the current debug stack frame. This can be achieve by either clicking on items in the window or using the U and D keys in debug mode. This will take the debug statement indicator to the return point for that stack level. This will not change the point where execution stopped and will be restarted from.
By changing the debug stack frame we are changing the context in which variables are debugged e.g. tooltipped, evaluated. It will also change the contents of the Local Variables window. This replaces the old workbenches method of debugging in the variables in the halted stack frame. If two variables defined at different stack levels do share the same name it is now possible to debug both.