1 files changed, 10 insertions, 3 deletions

diff --git a/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java b/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java
index e8f97d51..ae8c70e0 100644
--- a/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java
+++ b/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java
@@ -16,6 +16,7 @@ import org.eclipse.xtext.nodemodel.INode;
 import org.eclipse.xtext.nodemodel.util.NodeModelUtils;
 import org.eclipse.xtext.service.OperationCanceledManager;
 import org.eclipse.xtext.util.CancelIndicator;
+import org.jetbrains.annotations.NotNull;
 import tools.refinery.language.model.problem.*;
 import tools.refinery.language.utils.ProblemDesugarer;
 import tools.refinery.language.utils.ProblemUtil;
@@ -94,9 +95,16 @@ public class ProblemSemanticHighlightingCalculator extends DefaultSemanticHighli
         }
 
         protected String[] getHighlightClass(EObject eObject, EReference reference) {
+                boolean isError = ProblemUtil.isError(eObject);
                 if (ProblemUtil.isBuiltIn(eObject)) {
-                        return new String[] { BUILTIN_CLASS };
+                        var className = isError ? ERROR_CLASS : BUILTIN_CLASS;
+                        return new String[] { className };
                 }
+                return getUserDefinedElementHighlightClass(eObject, reference, isError);
+        }
+
+        @NotNull
+        private String[] getUserDefinedElementHighlightClass(EObject eObject, EReference reference, boolean isError) {
                 ImmutableList.Builder<String> classesBuilder = ImmutableList.builder();
                 if (eObject instanceof ClassDeclaration classDeclaration && classDeclaration.isAbstract()) {
                         classesBuilder.add(ABSTRACT_CLASS);
@@ -105,8 +113,7 @@ public class ProblemSemanticHighlightingCalculator extends DefaultSemanticHighli
                                 && desugarer.isContainmentReference(referenceDeclaration)) {
                         classesBuilder.add(CONTAINMENT_CLASS);
                 }
-                if (eObject instanceof PredicateDefinition predicateDefinition
-                                && predicateDefinition.getKind() == PredicateKind.ERROR) {
+                if (isError) {
                         classesBuilder.add(ERROR_CLASS);
                 }
                 if (eObject instanceof Node node) {