The last group of tools in the toolbar is always available, regardless of the current layer type or the current selected object. These are the Workspace tools, and are used to control your view of the project, but don't actually modify the project itself.
When the Pan Workspace tool is selected, you can click and drag in the working area to move the project side to side and up and down. Note that this isn't the same as moving the objects in your project - only your view of them is changing, not where they appear in the final image. A shortcut for the Pan Workspace tool is to click and drag in the working area using the right mouse button - it's a quick way to pan, regardless of what tool is selected in the toolbar.
The Zoom Workspace tool is similar to the Pan Workspace tool: it moves your view of the project, without modifying the objects themselves. With this tool, dragging the mouse zooms your view of the project in and out. A shortcut for the zoom tool is to click and drag in the working area using the right mouse button while holding down the shift key - it's a quick way to zoom, regardless of what tool is selected in the toolbar.
The Rotate Workspace tool is used to temporarily rotate the workspace. Think of drawing on paper - sometimes you might rotate the physical paper to draw from a different angle. The Rotate Workspace tool works in a similar way - sometimes (especially with the Freehand drawing tool) it may be helpful to orient the workspace in a different direction. A shortcut for the Rotate Workspace tool is to click and drag in the working area using the right mouse button while holding down the control key - it's a quick way to rotate, regardless of what tool is selected in the toolbar.
To get back to the normal view of the scene, you can select Reset from the View menu, click the Reset View button in the tool options area of the Moho window, or press the <home> key to reset the view.
The Orbit Workspace tool allows you to view your scene from outside the camera. It's like holding the scene in your handing and turning it around to look at it from different angles. This tool is mainly useful when you're working on a scene with 3D elements (layers with different depths, complex camera moves, etc.). Hold the <alt> key while using this tool to move your view forward and back.
After using this tool to change your view of the scene, a blue wedge will be visible in the scene, representing the location of the camera. To get back to the normal view of the scene, you can select Reset from the View menu, click the Reset View button in the tool options area of the Moho window, or press the <home> key to reset the view.