The Clean Image Control Palette is a floating dialog that can be positioned anywhere on the screen. It provides the controls to remove spots or dead pixels and noise from the active image.
This dialog is visible when you are in Clean image mode (i.e. the Clean image button 
is down).
To show or hide the Clean Image Control Palette, click View->Toolbars->Control Palette or press the 
button.
Noise reduction automatically applies spot removal.
Use the three sliders (and edit boxes) to set the amount of noise reduction:
% Amount sets the overall amount of noise reduction applied.
Radius sets the number of pixels over which the noise algorithm processes.
% Sensitivity sets the amount of detail that the algorithm preserves.
Press the delete button 
to set noise reduction to zero.