diff --git a/Source/KeyHandler.mm b/Source/KeyHandler.mm
index 38f02774..6a1fcc6f 100644
--- a/Source/KeyHandler.mm
+++ b/Source/KeyHandler.mm
@@ -372,6 +372,13 @@ static NSString *const kGraphVizOutputfile = @"/tmp/McBopomofo-visualization.dot
             // if the spacebar is NOT set to be a selection key
             if ([input isShiftHold] || !Preferences.chooseCandidateUsingSpace) {
                 if (_builder->cursorIndex() >= _builder->length()) {
+                    if ([state isKindOfClass:[InputStateNotEmpty class]]) {
+                        NSString *composingBuffer = [(InputStateNotEmpty *)state composingBuffer];
+                        if ([composingBuffer length]) {
+                            InputStateCommitting *committing = [[InputStateCommitting alloc] initWithPoppedText:composingBuffer];
+                            stateCallback(committing);
+                        }
+                    }
                     [self clear];
                     InputStateCommitting *committing = [[InputStateCommitting alloc] initWithPoppedText:@" "];
                     stateCallback(committing);