diff --git a/src/main/java/org/olat/ims/qti21/ui/editor/AssessmentTestComposerController.java b/src/main/java/org/olat/ims/qti21/ui/editor/AssessmentTestComposerController.java
index ed8c770b1bf5c7e2aed1bf56076fba900b358cfc..1e29a138d0a50afa6d219013262172ebac372e0a 100644
--- a/src/main/java/org/olat/ims/qti21/ui/editor/AssessmentTestComposerController.java
+++ b/src/main/java/org/olat/ims/qti21/ui/editor/AssessmentTestComposerController.java
@@ -1195,6 +1195,11 @@ public class AssessmentTestComposerController extends MainLayoutBasicController
 		if(confirmDeleteCtrl != null) return;
 		
 		TreeNode selectedNode = menuTree.getSelectedNode();
+		if(selectedNode == null) {
+			showWarning("warning.atleastone");
+			return;
+		}
+		
 		Object uobject = selectedNode.getUserObject();
 		if(uobject instanceof AssessmentTest) {
 			showWarning("error.cannot.delete");
diff --git a/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_de.properties b/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_de.properties
index b5f51d373fb22c8fb98bf7bcf71aa2b0a596455e..54843f3ff5e18f9fff019ad43b5d7db208bb4e06 100644
--- a/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_de.properties
+++ b/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_de.properties
@@ -153,6 +153,7 @@ tools.reload.from.files=Dateien neu laden und im Puffer ersetzen
 tools.reload.from.files.tooltip=Only visible to administrators.
 warning.alien.assessment.item=Dieser Fragetyp kann nicht mit dem OpenOLAT-Editor bearbeitet werden.
 warning.alien.assessment.test=Dieser Test kann nicht mit dem OpenOLAT-Editor bearbeitet werden.
+warning.atleastone=Bitte w\u00E4hlen Sie mindestens ein Element.
 warning.atleastonesection=Diese Sektion kann nicht gel\u00F6scht werden. Ein Test oder ein Test-Part muss mindestens eine Sektion enthalten.
 warning.feedback.cutvalue=Feedback wird aktiviert sobald bei "Notwendige Punktzahl f\u00FCr 'Bestanden'" eine Punktzahl eingegeben wurde.
 warning.in.use=Die Ressource wird bereits f\u00FCr Auswertung verwendet. Die Bearbeitung ist begrenzt.
diff --git a/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_en.properties b/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_en.properties
index 8fd4a92c65b04a4adf8910bde5af49ba43cb9682..f803608733cc7d6ded116787eee6af9f7d6d813f 100644
--- a/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_en.properties
+++ b/src/main/java/org/olat/ims/qti21/ui/editor/_i18n/LocalStrings_en.properties
@@ -153,6 +153,7 @@ tools.reload.from.files=Reload files and refresh cache
 tools.reload.from.files.tooltip=Only visible to administrators.
 warning.alien.assessment.item=This question type cannot be processed with the OpenOLAT editor.
 warning.alien.assessment.test=This test cannot be processed with the OpenOLAT editor.
+warning.atleastone=Please, choose at least one element.
 warning.atleastonesection=The section cannot be deleted. A test or a test part must contain at least one section.
 warning.feedback.cutvalue=The feedback is based on the cut value. You need to define it first.
 warning.in.use=The resource is already used for assessment purpose. Editing is limited.