The Select, Pan, Zoom and Zoom Out MapGuide map toolbar tools "stick". That is, the tools stay active until you pick another map tool or press the Esc key. You can pick the Zoom tool and keep clicking on the map to zoom, zoom, zoom.
Remember that you can press the keyboard Esc key to get back to the default tool and map cursor. Or, you can simply pick the "Select" tool on the MapGuide tool bar to get back to the default tool.