Create a new mask. See Creating Masks.
Click the Mask
Overlay toggle 
on the Layer palette to display the
mask overlay.
On the Tools toolbar, click the
Flood Fill tool 
.
Use a gradient, pattern, or texture mask to create interesting effects. A gradient mask varies the opacity of an image from fully hidden to fully shown. Use a gradient mask to fade an image in or out. A pattern or texture mask varies the image opacity in a repeated pattern throughout the image.
To create any of these masks, on the Materials palette select the material (gradient, pattern, or texture) and then fill the mask layer with it. When you choose a colored material, Paint Shop Pro converts it to greyscale before applying it.
To create a gradient, pattern, or texture mask:
Create a new mask. See Creating Masks.
Click the Mask
Overlay toggle on the Layer palette to display the
mask overlay.
On the Tools toolbar, click the
Flood Fill tool .
Note: To fill all pixels in the mask, on the Tool Options palette set the Match Mode to None.
On the Materials palette, select a gradient, texture, or pattern. See Choosing Gradients, Choosing Patterns, or Choosing Textures.
Left-click the mask to apply the foreground material; right-click the mask to apply the background material.
Changing the Mask Overlay Color