Bug 15604 Promote Fill arguments on method completion to a real preference
It is still in work in progress but it has become an established feature by now. Promote the preference to the code assist preference page.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavaEditorPreferencePage.java
private Control createColorPage(Composite parent) {
		
		Composite colorComposite= new Composite(parent, SWT.NULL);
		colorComposite.setLayout(new GridLayout());
		Composite backgroundComposite= new Composite(colorComposite, SWT.NULL);
		backgroundComposite.setLayout(new RowLayout());
		Label label= new Label(backgroundComposite, SWT.NULL);
		label.setText(JavaUIMessages.getString("JavaEditorPreferencePage.backgroundColor")); 
		SelectionListener backgroundSelectionListener= new SelectionListener() {
			public void widgetSelected(SelectionEvent e) {				
				boolean custom= fBackgroundCustomRadioButton.getSelection();
				fBackgroundColorButton.setEnabled(custom);
				fOverlayStore.setValue(AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT, !custom);
			}
			public void widgetDefaultSelected(SelectionEvent e) {}
		};
		fBackgroundDefaultRadioButton= new Button(backgroundComposite, SWT.RADIO | SWT.LEFT);
		fBackgroundDefaultRadioButton.setText(JavaUIMessages.getString("JavaEditorPreferencePage.systemDefault")); 
		fBackgroundDefaultRadioButton.addSelectionListener(backgroundSelectionListener);
		fBackgroundCustomRadioButton= new Button(backgroundComposite, SWT.RADIO | SWT.LEFT);
		fBackgroundCustomRadioButton.setText(JavaUIMessages.getString("JavaEditorPreferencePage.custom")); 
		fBackgroundCustomRadioButton.addSelectionListener(backgroundSelectionListener);
		fBackgroundColorEditor= new ColorEditor(backgroundComposite);
		fBackgroundColorButton= fBackgroundColorEditor.getButton();
		label= new Label(colorComposite, SWT.LEFT);
		label.setText(JavaUIMessages.getString("JavaEditorPreferencePage.foreground")); 
		label.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
		Composite editorComposite= new Composite(colorComposite, SWT.NONE);
		GridLayout layout= new GridLayout();
		layout.numColumns= 2;