Bug 99732 [build path] Exclusion filters are added on new source folder when unnecessary
In RC2. If you add a source folder inside another source folder, the outer folder's exclusion filters are updated to avoid ambiguity. Now, remove the inner folder from the class path, and re-add it. Every time this is done, the inner folder is added to the outer folder's exclusion filter, ad infinitum.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceContainerWorkbookPage.java
if (field == fFoldersList) {
			List selection= field.getSelectedElements();
			if (canEdit(selection)) {
				editEntry();
			}
		}
	}
		
	protected void sourcePageCustomButtonPressed(DialogField field, int index) {
		if (field == fFoldersList) {
			if (index == IDX_ADD) {
				CPListElement newElement= new CPListElement(fCurrJProject, IClasspathEntry.CPE_SOURCE);
				AddSourceFolderWizard wizard= newSourceFolderWizard(newElement, fFoldersList.getElements(), fOutputLocationField.getText());
				OpenBuildPathWizardAction action= new OpenBuildPathWizardAction(wizard);
				action.run();
			} else if (index == IDX_ADD_LINK) {
				List elementsToAdd= new ArrayList(10);
				CPListElement entry= openNewLinkedSourceContainerDialog(null);
				if (entry != null) {
					elementsToAdd.add(entry);
				}
				if (!elementsToAdd.isEmpty()) {
					if (fFoldersList.getSize() == 1) {
						CPListElement existing= (CPListElement) fFoldersList.getElement(0);
						if (existing.getResource() instanceof IProject) {
							askForChangingBuildPathDialog(existing);
						}
					}
					HashSet modifiedElements= new HashSet();
					askForAddingExclusionPatternsDialog(elementsToAdd, modifiedElements);