fix for BZDNG-173

modules/gui/src/python_shell/python_shell_widget.cc

@@ -737,6 +737,14 @@ QTextBlock PythonShellWidget::GetEditStartBlock()
 
 void PythonShellWidget::keyPressEvent(QKeyEvent* event)
 {
+  // BZDNG-173
+  if (event->key()==Qt::Key_Left) {
+    if (this->textCursor().position()==GetEditStartBlock().position() ||
+        this->textCursor().anchor()==GetEditStartBlock().position()) {
+      event->accept();
+      return;
+    }
+  }
   if (this->handle_custom_commands_(event)){
     return;
   }

modules/gui/src/python_shell/transition_guard.cc

@@ -37,7 +37,7 @@ EditPositionGuard::EditPositionGuard(PythonShellWidget* shell, int flags1, int f
 
 bool EditPositionGuard::check()
 {
-  return check_flag(flags1_) &&  check_flag(flags2_);
+    return check_flag(flags1_) &&  check_flag(flags2_);
 }
 
 bool EditPositionGuard::check_flag(int flags)