It is possible for your hotspots to “disappear” if you move the button that contains the visual scene image. Moving the image changes the stacking order of the buttons and sends the hotspots behind the image.
To recover those hotspots:
1. Select the Modify button in the top right corner of the page.
2. On the dialog that opens, select Settings, then Page Browser, select the page you wish to edit, then Editor
3. Select the visual scene image.
4. Move the visual scene image to the side of the screen.
5. Drag your hotspots to the other side of the screen.
6. Move the visual scene image back where it belongs.
7. Drag your hotspots back over the appropriate areas of the visual scene image. If you replace the image for a visual scene, be careful not to move the button that contains the image. Selecting it may cause restacking of the hotspots and the visual scene image.