diff --git a/Source/Modules/ControllerModules/KeyHandler.h b/Source/Modules/ControllerModules/KeyHandler.h
index 4aa5bd4a..730ab28a 100644
--- a/Source/Modules/ControllerModules/KeyHandler.h
+++ b/Source/Modules/ControllerModules/KeyHandler.h
@@ -39,6 +39,7 @@ extern InputMode imeModeNULL;
 
 @interface KeyHandler : NSObject
 
+- (BOOL)isBuilderEmpty;
 - (BOOL)handleInput:(KeyHandlerInput *)input
               state:(InputState *)state
       stateCallback:(void (^)(InputState *))stateCallback
diff --git a/Source/Modules/ControllerModules/KeyHandler.mm b/Source/Modules/ControllerModules/KeyHandler.mm
index eb042f1c..44cd1383 100644
--- a/Source/Modules/ControllerModules/KeyHandler.mm
+++ b/Source/Modules/ControllerModules/KeyHandler.mm
@@ -87,6 +87,14 @@ static NSString *const kGraphVizOutputfile = @"/tmp/vChewing-visualization.dot";
     return _inputMode;
 }
 
+- (BOOL)isBuilderEmpty {
+    if (_builder->grid().width() == 0) {
+        return YES;
+    } else {
+        return NO;
+    }
+}
+
 - (void)setInputMode:(NSString *)value
 {
     NSString *newInputMode;