}
} else if (!elem.isBuiltIn()) {
BuildpathAttributeConfiguration config = fAttributeDescriptors
.get(key);
if (config != null) {
IBuildpathAttribute result = config.performEdit(getShell(),
elem.getBuildpathAttributeAccess());
if (result != null) {
elem.setValue(result.getValue());
fLibraryList.refresh(elem);
}