diff --git a/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/.ratings b/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/.ratings
index 88368aa49edb5931f4db607746624e05b1c55fa8..de9d0fbc4fec47c0e42d4b80313b484d5f99068e 100644
--- a/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/.ratings
+++ b/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/.ratings
@@ -5,7 +5,7 @@ DynamicTextFieldTreeTableCell.java de24117e6f785b328f1ff62383626a0b4b54e8ff GREE
 DynamicTreeContentProviderBase.java 91896b1fb5104d126544c44c1ff8c30f2a13a8d6 GREEN
 DynamicTreeItem.java 7486071d20e896d6ca9a9101bf105caccf3656d0 GREEN
 DynamicTreeItemBase.java d883066ecc181120302ca32f328538de7a45b093 GREEN
-DynamicTreeTableUIProviderBase.java 7c534d8567fb88159977765cb7b6f60c21f1ab48 YELLOW
+DynamicTreeTableUIProviderBase.java 5bc7f6a74e379baa525f5d3420a95e558cbcbe90 YELLOW
 DynamicTreeTableViewer.java ead6f6671e9cb6b14632940bf440cba7e81fcd98 GREEN
 DynamicTreeUIProviderBase.java 82d3c051213f0147f4c67ad247a08696cee73110 GREEN
 DynamicTreeViewer.java 545f1ca10b7b3cad171b294a4b447875da45c9ed GREEN
diff --git a/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/DynamicTreeTableUIProviderBase.java b/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/DynamicTreeTableUIProviderBase.java
index 7c534d8567fb88159977765cb7b6f60c21f1ab48..5bc7f6a74e379baa525f5d3420a95e558cbcbe90 100644
--- a/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/DynamicTreeTableUIProviderBase.java
+++ b/org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/DynamicTreeTableUIProviderBase.java
@@ -48,6 +48,11 @@ import javafx.util.converter.DefaultStringConverter;
  */
 public abstract class DynamicTreeTableUIProviderBase<T> {
 	/**
+	 * Retrieves the label to be displayed in the given position.
+	 * 
+	 * Note: An empty cell can only be editable, if an empty String is returned here instead of
+	 * 'null'.
+	 * 
 	 * @param element
 	 *            the element to be displayed in the current row
 	 * @param column
@@ -347,9 +352,20 @@ public abstract class DynamicTreeTableUIProviderBase<T> {
 					@Override
 					public void updateItem(String item, boolean empty) {
 						super.updateItem(item, empty);
+
 						styleCell(this, columnIndex);
+					}
+
+					/** {@inheritDoc} */
+					@Override
+					public void startEdit() {
+						// null items are in cells, which cannot contain a value. Otherwise they
+						// would contain an empty String.
+						if(getItem() == null) {
+							return;
+						}
 
-						setEditable(item != null);
+						super.startEdit();
 					}
 				};
 
@@ -380,7 +396,7 @@ public abstract class DynamicTreeTableUIProviderBase<T> {
 		/** {@inheritDoc} */
 		@Override
 		public void startEdit() {
-			if(!isEditable() || !getTreeTableView().isEditable() ||
+			if(getItem() == null || !isEditable() || !getTreeTableView().isEditable() ||
 					!getTableColumn().isEditable()) {
 				return;
 			}