void (@NotNull final Editor editor, @NotNull final String placeholder) { final FoldingModel foldingModel = editor.getFoldingModel(); foldingModel.runBatchFoldingOperation(() -> { for (FoldRegion region : foldingModel.getAllFoldRegions()) { foldingModel.removeFoldRegion(region); } FoldRegion region = foldingModel.addFoldRegion(0, editor.getDocument().getTextLength(), placeholder); if (region != null) { region.setExpanded(false); } }); }