diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ProposalCollector.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ProposalCollector.java
index 9c4374b240a84477e78b9eec3cac578ad94dea49..b3c7bb571529c67239f7ca1e5e1218569c3f62b7 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ProposalCollector.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ProposalCollector.java
@@ -348,6 +348,10 @@ public final class ProposalCollector {
 		if (string == null) {
 			return -1;
 		}
+		
+		if (reference == null) {
+			return 0;
+		}
 
 		final List<ISubReference> subreferences = reference.getSubreferences();
 		if (subreferences.isEmpty()) {
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/AssignmentContext.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/AssignmentContext.java
index 714e0202cc5092a597f0f0627fe3019b7f56c2a1..64ccc41382f00c280ded744046eb73663dae36f8 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/AssignmentContext.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/AssignmentContext.java
@@ -29,6 +29,7 @@ public class AssignmentContext extends ProposalContext {
 	private AssignmentMatch aMatch;
 	
 	static {
+		basicTypes.put("boolean", Type_type.TYPE_BOOL);
 		basicTypes.put("bitstring", Type_type.TYPE_BITSTRING);
 		basicTypes.put("charstring", Type_type.TYPE_CHARSTRING);
 		basicTypes.put("float", Type_type.TYPE_REAL);
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/ProposalContext.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/ProposalContext.java
index 93c8941c52360c47263a77adf208ced4e8d30213..2c041bea80af7910add8f30c5d490e2d65673246 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/ProposalContext.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/editors/ttcn3editor/contentassist/ProposalContext.java
@@ -182,6 +182,7 @@ public abstract class ProposalContext {
 				propCollector.addProposal(item.getId(), ImageCache.getImageByType(ttype), "");
 			}
 			break;
+		case TYPE_BOOL:
 		case TYPE_BITSTRING:
 		case TYPE_CHARSTRING:
 		case TYPE_HEXSTRING:
@@ -189,6 +190,10 @@ public abstract class ProposalContext {
 		case TYPE_OCTETSTRING:
 		case TYPE_REAL:
 		case TYPE_UCHARSTRING:
+			if (ttype == Type_type.TYPE_BOOL) {
+				propCollector.addProposal("true", "true", ImageCache.getImageByType(ttype));
+				propCollector.addProposal("false", "false", ImageCache.getImageByType(ttype));
+			}
 			List<Definition> defList = getAvailableDefsByType(ttype);
 			for (Definition a : defList) {
 				if (! a.getIdentifier().getName().equals(excludeName)) {
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/graphics/ImageCache.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/graphics/ImageCache.java
index 1f654f7894120949942dd1f749d6363d525ff6a8..d6b0b57d01e3b713f530974897b6f13b5f5769ea 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/graphics/ImageCache.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/graphics/ImageCache.java
@@ -15,6 +15,7 @@ import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.titan.designer.AST.IType.Type_type;
 import org.eclipse.titan.designer.AST.TTCN3.types.BitString_Type;
+import org.eclipse.titan.designer.AST.TTCN3.types.Boolean_Type;
 import org.eclipse.titan.designer.AST.TTCN3.types.CharString_Type;
 import org.eclipse.titan.designer.AST.TTCN3.types.Component_Type;
 import org.eclipse.titan.designer.AST.TTCN3.types.Float_Type;
@@ -42,6 +43,7 @@ public final class ImageCache {
 	}
 	
 	static {
+		typeCache.put(Type_type.TYPE_BOOL, (new Boolean_Type()).getOutlineIcon());
 		typeCache.put(Type_type.TYPE_BITSTRING, (new BitString_Type().getOutlineIcon()));
 		typeCache.put(Type_type.TYPE_CHARSTRING, (new CharString_Type().getOutlineIcon()));
 		typeCache.put(Type_type.TYPE_COMPONENT, (new Component_Type(null).getOutlineIcon()));