diff --git a/app/src/main/java/org/solovyev/android/calculator/Calculator.java b/app/src/main/java/org/solovyev/android/calculator/Calculator.java
index 89e73f17..766f26a2 100644
--- a/app/src/main/java/org/solovyev/android/calculator/Calculator.java
+++ b/app/src/main/java/org/solovyev/android/calculator/Calculator.java
@@ -26,15 +26,16 @@ import android.content.SharedPreferences;
 import android.support.annotation.NonNull;
 import android.text.TextUtils;
 import android.util.Log;
+
 import com.squareup.otto.Bus;
 import com.squareup.otto.Subscribe;
-import jscl.*;
-import jscl.math.Generic;
-import jscl.math.function.Constants;
-import jscl.math.function.IConstant;
-import jscl.text.ParseInterruptedException;
+
 import org.solovyev.android.Check;
-import org.solovyev.android.calculator.calculations.*;
+import org.solovyev.android.calculator.calculations.CalculationCancelledEvent;
+import org.solovyev.android.calculator.calculations.CalculationFailedEvent;
+import org.solovyev.android.calculator.calculations.CalculationFinishedEvent;
+import org.solovyev.android.calculator.calculations.ConversionFailedEvent;
+import org.solovyev.android.calculator.calculations.ConversionFinishedEvent;
 import org.solovyev.android.calculator.functions.FunctionsRegistry;
 import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.android.calculator.variables.CppVariable;
@@ -45,11 +46,6 @@ import org.solovyev.common.msg.MessageType;
 import org.solovyev.common.text.Strings;
 import org.solovyev.common.units.ConversionException;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-import javax.inject.Named;
-import javax.inject.Singleton;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -57,6 +53,21 @@ import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicLong;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+import javax.inject.Named;
+import javax.inject.Singleton;
+
+import jscl.JsclArithmeticException;
+import jscl.MathEngine;
+import jscl.NumeralBase;
+import jscl.NumeralBaseException;
+import jscl.math.Generic;
+import jscl.math.function.Constants;
+import jscl.math.function.IConstant;
+import jscl.text.ParseInterruptedException;
+
 @Singleton
 public class Calculator implements SharedPreferences.OnSharedPreferenceChangeListener {
 
@@ -274,7 +285,7 @@ public class Calculator implements SharedPreferences.OnSharedPreferenceChangeLis
         if (!calculateOnFly) {
             return;
         }
-        if (TextUtils.equals(e.newState.text, e.oldState.text)) {
+        if (!e.shouldEvaluate()) {
             return;
         }
         evaluate(JsclOperation.numeric, e.newState.getTextString(), e.newState.sequence);
diff --git a/app/src/main/java/org/solovyev/android/calculator/Editor.java b/app/src/main/java/org/solovyev/android/calculator/Editor.java
index 4dd26105..4b388eb6 100644
--- a/app/src/main/java/org/solovyev/android/calculator/Editor.java
+++ b/app/src/main/java/org/solovyev/android/calculator/Editor.java
@@ -23,6 +23,8 @@
 package org.solovyev.android.calculator;
 
 import android.content.SharedPreferences;
+import android.text.TextUtils;
+
 import com.squareup.otto.Bus;
 import com.squareup.otto.Subscribe;
 import org.solovyev.android.Check;
@@ -87,6 +89,11 @@ public class Editor {
 
     @Nonnull
     public EditorState onTextChanged(@Nonnull EditorState newState) {
+        return onTextChanged(newState, false);
+    }
+
+    @Nonnull
+    public EditorState onTextChanged(@Nonnull EditorState newState, boolean force) {
         Check.isMainThread();
         if (textProcessor != null) {
             final TextProcessorEditorResult result = textProcessor.process(newState.getTextString());
@@ -97,7 +104,7 @@ public class Editor {
         if (view != null) {
             view.setState(newState);
         }
-        bus.post(new ChangedEvent(oldState, newState));
+        bus.post(new ChangedEvent(oldState, newState, force));
         return state;
     }
 
@@ -224,7 +231,7 @@ public class Editor {
     public void onEngineChanged(@Nonnull Engine.ChangedEvent e) {
         // this will effectively apply new formatting (if f.e. grouping separator has changed) and
         // will start new evaluation
-        onTextChanged(getState());
+        onTextChanged(getState(), true);
     }
 
     public static class ChangedEvent {
@@ -232,10 +239,16 @@ public class Editor {
         public final EditorState oldState;
         @Nonnull
         public final EditorState newState;
+        public final boolean force;
 
-        private ChangedEvent(@Nonnull EditorState oldState, @Nonnull EditorState newState) {
+        private ChangedEvent(@Nonnull EditorState oldState, @Nonnull EditorState newState, boolean force) {
             this.oldState = oldState;
             this.newState = newState;
+            this.force = force;
+        }
+
+        boolean shouldEvaluate() {
+            return force || !TextUtils.equals(newState.text, oldState.text);
         }
     }