diff --git a/SQCSim2021/engine.cpp b/SQCSim2021/engine.cpp
index 5afb035..fcdd44f 100644
--- a/SQCSim2021/engine.cpp
+++ b/SQCSim2021/engine.cpp
@@ -1877,9 +1877,6 @@ char Engine::SimulateKeyboard(unsigned char key) {
 		if (!m_keyShift) { m_inputChar = '9'; }
 		else { m_inputChar = ')'; }
 		break;
-	case 36: // SPACE
-		m_inputChar = ' ';
-		break;
 	case 38: // SHIFT
 		m_keyShift = true;
 		break;
@@ -1890,15 +1887,20 @@ char Engine::SimulateKeyboard(unsigned char key) {
 		if (!m_keyShift) { m_inputChar = '-'; }
 		else { m_inputChar = '_'; }
 		break;
+	case 57: // SPACE
+		m_inputChar = ' ';
+		break;
 	default:
+		m_invalidChar = true;
 		break;
 	}
 
-	if ((int)key != 38) {
+	if ((int)key != 38 && !m_invalidChar) {
+		m_charChanged = true;
 		std::cout << "Key pressed: " << (int)key << " (" << m_inputChar << ")" << std::endl;
 	}
 
-	m_charChanged = true;
+	m_invalidChar = false;
 	return m_inputChar;
 }
 
diff --git a/SQCSim2021/engine.h b/SQCSim2021/engine.h
index b99fd76..1f8363f 100644
--- a/SQCSim2021/engine.h
+++ b/SQCSim2021/engine.h
@@ -203,8 +203,9 @@ private:
     bool m_selectedOptions = false;
     bool m_selectedQuit = false;
 
-    char m_inputChar = 0;
     std::string m_currentInputString;
+    char m_inputChar = 0;
+    bool m_invalidChar = false;
     bool m_charChanged = false;
     
     bool m_key1 = false;