There is an SDL 1.2 bug where when you press both mouse buttons at the same time, it does what its supposed to do: Zooming in on the map, but you can't ever cancel it and it just zooms in indefinitely. Then, when you exit to the main menu and reload the map, it won't matter: this time, not only will both mouse buttons do this, but also the right mouse button alone too. So, you gotta restart the entire program.
