diff --git a/scanslicer/ui_builders_preview.py b/scanslicer/ui_builders_preview.py
index 25cf290..fab0dcb 100644
--- a/scanslicer/ui_builders_preview.py
+++ b/scanslicer/ui_builders_preview.py
@@ -184,3 +184,6 @@ class ScanSlicerUiPreviewMixin(ScanSlicerUiSharedMixin):
         status_filename_layout.setSpacing(0)
         status_filename_layout.addWidget(self.status_filename_label)
         status_bar.addPermanentWidget(status_filename_container)
+
+
+__all__ = ["ScanSlicerUiPreviewMixin"]