why do apps try and open on a monitor that is not connected

Hello Technology Team,

Thank you for posting question on Microsoft Windows Forum.

Based on your query of apps keeping to try and open on monitors being disconnected after removing laptop from docking station.

The potential cause might be of when undocking or disconnecting external monitors. The operating system retains the memory of your old monitor configuration. Even though, those screens are not connected anymore. You can try the following suggested steps to fix the issue.

1. Open Settings.
2. Navigate to System → Display.
3. Scroll down to the Multiple displays section.
4. Make sure the option “Remember window locations based on monitor connection” is checked.
5. Also making sure to check the box for "Minimize windows when a monitor is disconnected."
6. 

Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same issue too.