The Flood Fill tool fills the pixels that you click, and neighboring pixels of similar color, with the specified foreground color. Neighboring pixels are only filled if their values fall within the flood fill's Tolerance range (see Editing Flood Fills/Magic Wand Selections).
When you click a given pixel, it is filled and its neighbors are evaluated to see if they fall within the Tolerance range. Pixels falling within the range are filled and their neighbors are, in turn, evaluated to see if they fall within the Tolerance range. This continues until none of the evaluated pixels fall within the Tolerance range.
Edit the paint operator whose pixels you want to fill, as described in Editing and Previewing Paint Operators.
Choose a color for the fill as described in Choosing Colors with the Fx Color Selector. Flood filling uses the foreground color.
Set the Flood Fill tool properties as described in the following section, Editing Flood Fills/Magic Wand Selections.
From the Paint menu in the Fx viewer, choose Draw 
Flood Fill Tool.
Alternatively, you can position the mouse pointer over the Fx viewer and press U.
In the Fx Viewer, click a pixel of the color that you want to fill.
The pixel that you click, and any adjacent pixels whose color values are within the flood fill's Tolerance range, are filled with the foreground color.
Setting the Flood Fill/Magic Wand Properties
The Flood Fill/Magic Wand page of the Paint Tool Settings property editor is where you define how the Flood Fill tool fills pixels and how The Magic-Wand stencil tool selects them.
The Magic Wand stencil tool is to selection what the Flood Fill tool is to painting. It selects regions of the image using the exact same settings that the Flood Fill tool uses to fill them.
For more information about the Magic wand tool, and stencil tools in general, see Viewing the Paint Selection Mask.
If you are applying a flood fill to a raster paint clip, you must set the Flood Fill tool's properties before applying the fill because you won't be able to change it after it's applied. This is helpful, but not necessary, in vector paint operators since you can edit each fill after you apply it, as described in Painting with Color Shapes.
To set the flood fill/magic wand properties
From the Fx viewer paint menu, choose Tools Paint Tool Settings to open the Paint Tool Settings property editor.
Alternatively, you can position the mouse pointer over the Fx viewer and press 3.
On the Flood Fill/Magic Wand page, choose a fill Mode to specify the method for determining which pixels are filled/selected. Two modes are available:
RGB: neighboring pixels are filled/selected if their RGB values match those of the clicked pixel. Set the Tolerance value to define how closely a neighboring pixel's RGB values must match those of the clicked pixel before the pixel is filled/selected.
A value of 0 means that only pixels that match the clicked pixel exactly are filled/selected. Raising the Tolerance value broadens the range of "matching" RGB values such that pixels with increasingly dissimilar RGB values are filled/selected. Setting the value to 100 fills/selects the entire image.
HSV: neighboring pixels are filled/selected if their Hue, Saturation, and/or Value values match those of the clicked pixel. Adjust the Hue, Saturation, and/or Value settings to define how closely a neighboring pixel's values must match those of the clicked pixel before the pixel is filled/selected.
As with the RGB mode's Tolerance setting, the lower the values, the more closely a pixel must match the selected pixel's Hue, Saturation, and/or Value value before it is filled/selected.
Activate the Anti Alias option to soften the edges of the filled/selected area. The fill/selection falls off at the edges over a distance defined by the Tolerance setting.
Adjust the Feather setting to blur the edge of the filled/selected area. The higher the value, the larger the blurred area.
Editing Flood Fills/Magic Wand Selections
Each time you use the Flood Fill tool in a vector paint operator, a Flood Fill shape is created at the click location. Similarly each time you use the Magic Wand tool in any paint operator, a Magic Wand shape is created at the click location. In either case, editing the shape opens a property editor from which you can alter the fill/selection after you've applied it.
In the Fx viewer, the center of the shape's control object corresponds to the clicked pixel. You can translate the control object to apply the fill to/select a different pixel. The new pixel's neighbors are also filled, according to the fill's Tolerance setting.
To edit a Flood Fill / Magic Wand shape's properties
Edit the vector paint operator whose Flood Fill or Magic Wand shape you wish to edit, as described in Editing and Previewing Paint Operators.
In the Fx Viewer, activate the Select Shape tool (press Space), select the Flood Fill or Magic Wand object and press Enter.
The FloodFill or Magic Wand property editor opens and the shape's control object is highlighted in the Fx Viewer.
From the Flood Fill or Magic Wand tab of the property editor, adjust the fill/selection properties as necessary. These are the same properties described, Editing Flood Fills/Magic Wand Selections, but they are applied retroactively.
You can also set additional properties, depending on whether you're editing a Flood Fill Shape or a Magic Wand shape.
If you are adjusting a Flood Fill shape, you can adjust the fill's Fill Color and Opacity settings to change the color and opacity of the fill respectively.
If you are adjusting a Magic Wand shape, you can set the selection Action, which controls whether the Magic Wand selection added to existing selections, removed from existing selections, and so on. See Overview of Editing Shapes for details.
To translate a Flood Fill / Magic Wand shape in the Fx viewer
Edit the shape's properties, as described in the previous procedure and, from the Transform tab of the Flood Fill or Magic Wand property editor, adjust the X and Y values to translate the fill shape horizontally and vertically.
Drag the shape's control object to a new location in the Fx Viewer.
As soon as you change the shape's position, the fill/selection is applied to the new pixel and its neighbors.
