protected Color getCompletionBackground(T sel, boolean isSelected, boolean cellHasFocus) {
		return null;
	}
Get the background color to display for the given suggestion in the list

@param sel the suggestion to display
@param isSelected true if the suggestion is currently selected
@param cellHasFocus true if the suggestion currently has focus
@return the background color for the suggestion
Ghidra/Framework/Docking/src/main/java/docking/widgets/autocomplete/TextFieldAutocompleter.java