When the graph editor panel is maximized, panning with middle-mouse-button un-maximizes it.

1. Create a new project.
2. Create a new composition.
3. Add a new layer of any kind. Add a few keyframes to some value.
4. Select the keyframes and open the graph editor.
5. Press tilde (`) to maximize the graph editor panel inside After Effects.
6. Use the middle mouse button to pan/scroll inside the graph editor.
7. The graph editor panel erroneously returns to its original size.

If no layers are selected, the problem does not occur. It also doesn’t happen when holding spacebar to pan/scroll.