Switching photos doesn't re-enforce the zoom to fit, allowing a "too zoomed out" situation.
- Run in debug mode.
- Open p39.zip. On a 1920×1080 Win10 display, the zoom will probably be somewhere around 100%.
- Select the last photo (landscape-oriented "Pyrrhocoris3-etac2"). Unexpectedly, the zoom level stays the same (if it had been changed to, e.g., 108%, it would be 108% now), leaving empty space around the photo.
- Scroll the mouse wheel down to change the zoom (zoom out). It will be clamped to around 133%, to fit the photo. The zoom won't change below this ~133% value.