diff --git a/org.adempiere.base/src/org/idempiere/expression/logic/EvaluationVisitor.java b/org.adempiere.base/src/org/idempiere/expression/logic/EvaluationVisitor.java
index 07359a884b..8cd9bfd1ba 100644
--- a/org.adempiere.base/src/org/idempiere/expression/logic/EvaluationVisitor.java
+++ b/org.adempiere.base/src/org/idempiere/expression/logic/EvaluationVisitor.java
@@ -138,6 +138,8 @@ public class EvaluationVisitor extends SimpleBooleanBaseVisitor<Object> {
 	private Boolean isEqual(SimpleBooleanParser.ComparatorExpressionContext ctx) {
 		Comparable left = asComparable(ctx.left);
 		Comparable right = asComparable(ctx.right);
+		if (left == null && right == null)
+			return Boolean.TRUE;
 		if (left == null || right == null)
 			return Boolean.FALSE;
 		if (left instanceof String && right instanceof String && !(ctx.right.getText().startsWith("'") && !(ctx.right.getText().startsWith("\"")))) {
diff --git a/org.idempiere.test/src/org/idempiere/test/base/LogicExpressionTest.java b/org.idempiere.test/src/org/idempiere/test/base/LogicExpressionTest.java
index 81037bedc5..f168de0483 100644
--- a/org.idempiere.test/src/org/idempiere/test/base/LogicExpressionTest.java
+++ b/org.idempiere.test/src/org/idempiere/test/base/LogicExpressionTest.java
@@ -543,6 +543,28 @@ public class LogicExpressionTest  extends AbstractTestCase {
 		assertTrue(LogicEvaluator.evaluateLogic(evaluatee, expr));
 	}
 	
+	@Test
+	public void testEmptyStringExpression() {
+		String expr = "@ColumnSQL@=''";
+		Env.setContext(Env.getCtx(), "ColumnSQL", (String)null);
+		assertTrue(LegacyLogicEvaluator.evaluateLogic(evaluatee, expr));
+		
+		Env.setContext(Env.getCtx(), "ColumnSQL", (String)null);
+		assertTrue(LogicEvaluator.evaluateLogic(evaluatee, expr));
+		
+		expr = "@ColumnSQL@!''";
+		
+		Env.setContext(Env.getCtx(), "ColumnSQL", (String)null);
+		assertFalse(LegacyLogicEvaluator.evaluateLogic(evaluatee, expr));
+		Env.setContext(Env.getCtx(), "ColumnSQL", "now()");
+		assertTrue(LegacyLogicEvaluator.evaluateLogic(evaluatee, expr));
+		
+		Env.setContext(Env.getCtx(), "ColumnSQL", (String)null);
+		assertFalse(LogicEvaluator.evaluateLogic(evaluatee, expr));
+		Env.setContext(Env.getCtx(), "ColumnSQL", "now()");
+		assertTrue(LogicEvaluator.evaluateLogic(evaluatee, expr));
+	}
+	
 	private static class ContextEvaluatee implements Evaluatee {
 
 		@Override