diff --git a/src/main/java/org/olat/core/gui/components/textboxlist/_static/js/multiselect.js b/src/main/java/org/olat/core/gui/components/textboxlist/_static/js/multiselect.js
index a78b0a863035d1fd4d27d03eb9821fc15dfb7646..2518ab0ec41243516596a2d9970a6bf56de14f77 100644
--- a/src/main/java/org/olat/core/gui/components/textboxlist/_static/js/multiselect.js
+++ b/src/main/java/org/olat/core/gui/components/textboxlist/_static/js/multiselect.js
@@ -793,6 +793,20 @@ var ProtoMultiSelect = Class.create(TextboxList, {
 				);
 			}
 			
+			if(matches && !this.options.get('allowDuplicates')) {
+				var toDelete = new Array();
+				var count = 0;
+				for(var i=0; i<matches.length; i++) {
+					var val = matches[i].evalJSON(true).value;
+					if(this.foundInSelectedValues(val)) {
+						toDelete[count++] = matches[i];
+					}	
+				}
+				for(var i=0;i<toDelete.length; i++) {
+					matches.remove(toDelete[i]);
+				}
+			}
+			
 			if (this.options.get('sortResults')) {
 				matches = matches.sortBy(function(el) { return el.evalJSON(true).caption });
 			}