Move: With pressed left and right mouse key you can shift the whole content.

Fit in: Perform a double-click with pressed Ctrl key. -> The whole content of the sketcher is fitted in the window.

Zoom rectangle: Drag a rectangle with pressed middle mouse button.

Selection rectangle: Drag a rectangle with pressed shift key and left mouse button.

Multi selection: Click on the desired elements with pressed Ctrl key.

Mouse wheel: With the Mouse wheel, you can zoom in and out. Turning downwards will reduce the image. If Invert is active exactly the other way round. Depending on where positioning the mouse cursor before scrolling the mouse wheel, the object's position is adjusted.