Bug 41523 Keep Order of libs when editing library [build path]
When I edit a library in the Properties dialog of my project using "Properties"->"Java Build Path"->"Libraries"->"Edit", e.g. changing the JRE from 1.4 to 1.3, or changing from an old version of a JAR to a newer one, the changed library is at the last position in the classpath. It should kept at the position it was.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceContainerWorkbookPage.java
protected void sourcePageSelectionChanged(DialogField field) {
		List selected= fFoldersList.getSelectedElements();
		fFoldersList.enableButton(IDX_EDIT, canEdit(selected));
		fFoldersList.enableButton(IDX_REMOVE, canRemove(selected));
	}
	
	private void removeEntry() {
		List selElements= fFoldersList.getSelectedElements();
		for (int i= selElements.size() - 1; i >= 0 ; i--) {
			Object elem= selElements.get(i);
			if (elem instanceof CPListElementAttribute) {
				CPListElementAttribute attrib= (CPListElementAttribute) elem;
				String key= attrib.getKey();
				Object value= key.equals(CPListElement.EXCLUSION) ? new Path[0] : null;
				attrib.getParent().setAttribute(key, value);
				selElements.remove(i);
			}
		}
		if (selElements.isEmpty()) {
			fFoldersList.refresh();
			fClassPathList.dialogFieldChanged(); 
		} else {
			fFoldersList.removeElements(selElements);
		}
	}
	
	private boolean canRemove(List selElements) {
		if (selElements.size() == 0) {
			return false;
		}