If you lock a window completely inside another. Example is model viewer completely within the editor. Then when you focus the main editor, the model viewer will go behind it. But because it is locked, it's position will move as the parent element does. This means you have to cycle the toggle button to get the window back in front.
Notice the window is locked, inside the main editor
Model viewer button 'active', but the model viewer is behind the main editor, yet still locked and parented.
If you lock a window completely inside another. Example is model viewer completely within the editor. Then when you focus the main editor, the model viewer will go behind it. But because it is locked, it's position will move as the parent element does. This means you have to cycle the toggle button to get the window back in front.
Notice the window is locked, inside the main editor
Model viewer button 'active', but the model viewer is behind the main editor, yet still locked and parented.