Fix a null reference exception.

Author: Mailaender

chemclipse/plugins/org.eclipse.chemclipse.model/src/org/eclipse/chemclipse/model/support/ChromatogramColumnSupport.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2023, 2025 Lablicate GmbH.
+ * Copyright (c) 2023, 2026 Lablicate GmbH.
  *
  * This program and the accompanying materials are made
  * available under the terms of the Eclipse Public License 2.0
@@ -50,7 +50,7 @@ public static void parseSeparationColumn(IChromatogram chromatogram, ColumnField
 			 */
 			if(parseReferences) {
 				for(IChromatogram chromatogramReference : chromatogram.getReferencedChromatograms()) {
-					if(chromatogramReference.isParseSeparationColumnEnabled()) {
+					if(chromatogramReference != null && chromatogramReference.isParseSeparationColumnEnabled()) {
 						mapSeparationColumn(chromatogramReference, columnField, separationColumnMapping);
 					}
 				}