A mask is a four-sided, shape-able layer that allows you to hide other
layers from a selected portion of your screen excluding the
background.
To create the Mask select the Add New Mask button on the left panel.
You can click and drag the mask by left-clicking within the mask and
moving the mask near the desired location.
After clicking and dragging the four sided Mask to where you want it,
you can now select each corner (one at a time) and move it to follow
the shape of your object. On the Windows version of Fire Studio 7, the mask no longer has red control points on each corner. The mask still functions exactly the same, simply drag each corner to the desired position.
You can only form the mask into a four point shape, so if you need to work with
a complicated shape, you’ll need to use additional masks.
If the mask isn't visible, try pressing the "space bar" on your computer. The space bar toggles the outline of the mask (and all other layers) on and off.