message: Don't use event browser as area reference if it's not visible.
  * Fixes a crash opening the API inspector if the event browser was
  closed.
diff: @@ -1404,7 +1404,8 @@ void MainWindow::on_action_API_Inspector_triggered()
  }
  else
  {
  - if(m_Ctx.HasEventBrowser())
  + if(m_Ctx.HasEventBrowser() &&
  + ui->toolWindowManager->toolWindows().contains(m_Ctx.GetEventBrowser()->Widget()))
  {
  ToolWindowManager::AreaReference ref(
  ToolWindowManager::BottomOf,
  