QGIS 2.2 includes many improvements to help you navigate your compositions. You can now zoom in or out from a composition by using the mouse scroll wheel. A dedicated pan tool has been added which allows you to drag the composition around, and you can also switch immediately to pan mode by holding the space bar or the by holding the mouse scroll wheel. There's also a new zoom tool which allows you to precisely zoom to a specific area of your composition. You can also switch to zoom mode at any time by pressing and holding control-space and drawing a zoom region on the composition.