diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index b784cf3db..32da5d74f 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -25,6 +25,7 @@ use Slic3r::GUI::Plater::3DPreview;
 use Slic3r::GUI::Plater::ObjectPartsPanel;
 use Slic3r::GUI::Plater::ObjectCutDialog;
 use Slic3r::GUI::Plater::ObjectSettingsDialog;
+use Slic3r::GUI::Plater::LambdaObjectDialog;
 use Slic3r::GUI::Plater::OverrideSettingsPanel;
 use Slic3r::GUI::Preferences;
 use Slic3r::GUI::ProgressStatusBar;