diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/controls/PeekSource.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/controls/PeekSource.java
index b06dfa9a9c04d9513b6bac7b6df06074153ad220..af7ce5871a33276758070d2446a146f87f08779a 100755
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/controls/PeekSource.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/controls/PeekSource.java
@@ -124,7 +124,7 @@ public class PeekSource {
 		}
 		
 		IDocument doc = new Document(source);
-		CodeScanner scanner = new CodeScanner(new ColorManager());
+		CodeScanner scanner = new CodeScanner(new ColorManager(), true);
 		scanner.setRange(doc, 0, source.length());
 		IToken token;
 		StringBuilder codestr = new StringBuilder("<pre>");
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/CodeScanner.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/CodeScanner.java
index 4550e90549c07a2ae1f8a493455ebc1105d36607..1f4ee499449b4fab0d593ef7f3a034d5ff135fdf 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/CodeScanner.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/CodeScanner.java
@@ -109,7 +109,11 @@ public final class CodeScanner extends RuleBasedScanner implements IDocumentGett
 	public static final String[] VISIBILITY_MODIFIERS = new String[] { "public", "private", "friend" };
 
 	public CodeScanner(final ColorManager colorManager) {
-		final List<IRule> rules = getTTCNRules(colorManager);
+		this(colorManager, false);
+	}
+	
+	public CodeScanner(final ColorManager colorManager, boolean skipSemanticHighlightingRule) {
+		final List<IRule> rules = getTTCNRules(colorManager, skipSemanticHighlightingRule);
 
 		// line marker (single line preprocessor directive)
 		final IToken preprocessor = colorManager.createTokenFromPreference(PreferenceConstants.COLOR_PREPROCESSOR);
@@ -118,6 +122,10 @@ public final class CodeScanner extends RuleBasedScanner implements IDocumentGett
 	}
 
 	public static List<IRule> getTTCNRules(final ColorManager colorManager) {
+		return getTTCNRules(colorManager, false);
+	}
+	
+	public static List<IRule> getTTCNRules(final ColorManager colorManager, boolean skipSemanticHighlightingRule) {
 		final IToken keyword = colorManager.createTokenFromPreference(PreferenceConstants.COLOR_TTCN3_KEYWORDS);
 		final IToken templateMatch = colorManager.createTokenFromPreference(PreferenceConstants.COLOR_TEMPLATE_MATCH);
 		final IToken types = colorManager.createTokenFromPreference(PreferenceConstants.COLOR_TYPE);
@@ -145,7 +153,8 @@ public final class CodeScanner extends RuleBasedScanner implements IDocumentGett
 		rules.add(new StringDetectionPatternRule("'", new char[][] { { '\'', 'B' }, { '\'', 'H' }, { '\'', 'O' } }, string));
 		rules.add(new NumberDetectionPatternRule(ninteger, nfloat));
 		
-		final WordRule wordRule = new AstWordRule(new WordDetector(), other);
+		final WordRule wordRule = skipSemanticHighlightingRule ?
+			new WordRule(new WordDetector(), other) : new AstWordRule(new WordDetector(), other);
 		for (final String element : CodeScanner.KEYWORDS) {
 			wordRule.addWord(element, keyword);
 		}