Zoom: When your mouse hover on slice image, then use mouse wheel to zoom image.
Pan: When your mouse hover on slice image, and use mouse right click on image, then drag image to pan.
Undo:
In GUI click undo; or
on keyborad using ctrl+z (windows) / command+z(mac).
Switch slice: Press shift on your keyboard (do not release it when you switch slice), then use mouse left click the image
to drag up and down. When the switch is made to the image you want, you can release the shift key.