Bug 13034 Cannot create a Source Folder in a new Java Project
build 20020404 If you try and create a Source Folder in a Java Project you have just created you get an error preventing you from hitting finish. STEPS 1) Create Java Project Foo 2) Open New->Source Folder 3) Enter Bar as the name - you will get "Cannot nest entry Bar inside entry Foo/Bar" 4) Create a folder Bar. 5) Add it as a source folder in the Properties Dialog for Foo. No problem.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/NewSourceFolderWizardPage.java
public void changeControlPressed(DialogField field) {
			packRootChangeControlPressed(field);
		}
		
		
		public void dialogFieldChanged(DialogField field) {
			packRootDialogFieldChanged(field);
		}
	}
	private void packRootChangeControlPressed(DialogField field) {
		if (field == fRootDialogField) {
			IFolder folder= chooseFolder();
			if (folder != null) {
				IPath path= folder.getFullPath().removeFirstSegments(1);
				fRootDialogField.setText(path.toString());
			}
		} else if (field == fProjectField) {
			IJavaProject jproject= chooseProject();
			if (jproject != null) {
				IPath path= jproject.getProject().getFullPath().makeRelative();
				fProjectField.setText(path.toString());
			}
		}
	}	
	
	private void packRootDialogFieldChanged(DialogField field) {
		if (field == fRootDialogField) {
			updateRootStatus();