Mouse actions only use the left and right mouse buttons and dragging. Currently, the middle mouse button is not used.
To zoom in on an area click with the left mouse to establish a corner an drag along the diagonal to create a zoom box. Upon release the map will zoom in on the enclosed area. Please note that if Zoom Isotropic is set under the File pulldown then the box will NOT follow the cursor but will maintain a 1 to 1 map aspect ratio.
"Infinite" zooming in is not allowed. At some point the program will refuse to allow any further zooming in. Further, if a zoom area is too small then zooming will not take place. This is done to keep accidental left mouse single clicks on the map to cause an unwanted zoom.
Finally, if any edge of the zoom box falls off the map the zoom will not occur.
Right mouse clicks create a latitude longitude label on the map. These labels only remain as long as the map is not updated, resized, or zoomed in. They may be cleared with the Clear Labels... under the Action pull down.