Thanks for the investigation! There are more places where m_addressInput is used without a nullptr check, but I didn't analyze the code flow if these can be reached when the m_addressInput widget is not present. Feel free to verify :)

In D26917#600766, @cfeck wrote:

Thanks for the investigation! There are more places where m_addressInput is used without a nullptr check, but I didn't analyze the code flow if these can be reached when the m_addressInput widget is not present. Feel free to verify :)

I looked around and could not find any other instances where m_addressInput is used before it is created. However, during the investigation I found that the command-line option --fullscreen is not honored unless there is also a URL. I will file a new diff for you to consider