List<PropertiesFile> (@NotNull Project project, @NotNull List<? extends PropertiesFile> propertiesFiles) { final ProjectFileIndex fileIndex = ProjectRootManager.getInstance(project).getFileIndex(); final List<PropertiesFile> result = new ArrayList<>(propertiesFiles.size()); for (final PropertiesFile file : propertiesFiles) { if (!fileIndex.isInLibrary(file.getVirtualFile())) { result.add(file); } } return result; }