Index: lams_common/src/java/org/lamsfoundation/lams/qb/model/QbQuestion.java
===================================================================
diff -u -r6027dca0125bccd15dcdae16bc108177f85e7f73 -rb58f96e55bbc04e78723b11b77b2159aac191239
--- lams_common/src/java/org/lamsfoundation/lams/qb/model/QbQuestion.java	(.../QbQuestion.java)	(revision 6027dca0125bccd15dcdae16bc108177f85e7f73)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/model/QbQuestion.java	(.../QbQuestion.java)	(revision b58f96e55bbc04e78723b11b77b2159aac191239)
@@ -165,7 +165,7 @@
     @Cache(usage = CacheConcurrencyStrategy.TRANSACTIONAL)
     private List<QbOption> qbOptions = new ArrayList<>();
 
-    @OneToMany(mappedBy = "qbQuestion", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
+    @OneToMany(mappedBy = "qbQuestion", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
     @Fetch(FetchMode.SELECT)
     @Cache(usage = CacheConcurrencyStrategy.TRANSACTIONAL)
     private List<QbQuestionUnit> units = new ArrayList<>();
Index: lams_common/src/java/org/lamsfoundation/lams/qb/model/QbQuestionUnit.java
===================================================================
diff -u -r2188972474f8d186d6811e3dea2e4136be669335 -rb58f96e55bbc04e78723b11b77b2159aac191239
--- lams_common/src/java/org/lamsfoundation/lams/qb/model/QbQuestionUnit.java	(.../QbQuestionUnit.java)	(revision 2188972474f8d186d6811e3dea2e4136be669335)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/model/QbQuestionUnit.java	(.../QbQuestionUnit.java)	(revision b58f96e55bbc04e78723b11b77b2159aac191239)
@@ -2,7 +2,6 @@
 
 import java.io.Serializable;
 
-import javax.persistence.Cacheable;
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
@@ -32,7 +31,7 @@
 
     @Column
     private String name;
-    
+
     @Column
     private float multiplier = 0;
 
@@ -65,7 +64,7 @@
 
     @Override
     public int hashCode() {
-	return new HashCodeBuilder().append(this.name).append(this.multiplier).toHashCode();
+	return new HashCodeBuilder().append(this.name).append(this.multiplier).append(this.displayOrder).toHashCode();
     }
 
     @Override
Index: lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java
===================================================================
diff -u -r6027dca0125bccd15dcdae16bc108177f85e7f73 -rb58f96e55bbc04e78723b11b77b2159aac191239
--- lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java	(.../QbService.java)	(revision 6027dca0125bccd15dcdae16bc108177f85e7f73)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java	(.../QbService.java)	(revision b58f96e55bbc04e78723b11b77b2159aac191239)
@@ -995,14 +995,29 @@
 	}
 	// set units
 	if (type == QbQuestion.TYPE_NUMERICAL) {
-	    Set<QbQuestionUnit> unitList = getUnitsFromRequest(request, true);
-	    qbQuestion.getUnits().clear();
+	    Set<QbQuestionUnit> unitsFromRequest = getUnitsFromRequest(request, true);
+	    List<QbQuestionUnit> existingUnits = qbQuestion.getUnits();
+	    List<QbQuestionUnit> newUnits = new ArrayList<>();
 	    int displayOrder = 0;
-	    for (QbQuestionUnit unit : unitList) {
+	    for (QbQuestionUnit unit : unitsFromRequest) {
 		unit.setQbQuestion(qbQuestion);
 		unit.setDisplayOrder(displayOrder++);
-		qbQuestion.getUnits().add(unit);
+		newUnits.add(unit);
 	    }
+	    qbQuestion.setUnits(newUnits);
+
+	    for (QbQuestionUnit existingUnit : existingUnits) {
+		boolean unitFound = false;
+		for (QbQuestionUnit unit : newUnits) {
+		    if (unit.getUid() != null && unit.getUid().equals(existingUnit.getUid())) {
+			unitFound = true;
+			break;
+		    }
+		}
+		if (!unitFound) {
+		    qbDAO.delete(existingUnit);
+		}
+	    }
 	}
 
 	return qbQuestion.isQbQuestionModified(oldQuestion);