Canvas Tools Eyedropper
From PanelForge 4 Documentation
Eyedropper Tool
Set the current Canvas Workspace colour by clicking the cursor on an existing colour in the Canvas view.
How this colour is determined can be controlled using the following settings:
Sample All Visible Layers
If this checkbox is deactivated the pixel colour sampling will be restricted to current Canvas Layer. When active the full composite of all the Canvas Layers will be used during colour sampling.