When you close the plot window, it also closes the Plot/Export config dialog. Note that this issue does not exist in OR 23.09, only in the latest unstable.

Steps to reproduce:

1. Open 'A simple model rocket'
2. Go to the 'Flight simulations' tab
3. Click the "Plot / Export" button
4. Click the "Plot" button
5. Close the plot window with the "Close" button
6. The "Edit simulation window is now also closed...