Bug 23459 add preference option to turn off variable guessing on method completion
request from Adam
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavaEditorPreferencePage.java
label.setText(JavaUIMessages.getString("JavaEditorPreferencePage.preview")); 
		label.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
		
		Control previewer= createPreviewer(colorComposite);
		gd= new GridData(GridData.FILL_BOTH);
		gd.widthHint= convertWidthInCharsToPixels(20);
		gd.heightHint= convertHeightInCharsToPixels(5);
		previewer.setLayoutData(gd);
		
		fSyntaxColorList.addSelectionListener(new SelectionListener() {
			public void widgetDefaultSelected(SelectionEvent e) {
				
			}
			public void widgetSelected(SelectionEvent e) {
				handleSyntaxColorListSelection();
			}
		});
		
		foregroundColorButton.addSelectionListener(new SelectionListener() {
			public void widgetDefaultSelected(SelectionEvent e) {
				
			}
			public void widgetSelected(SelectionEvent e) {
				int i= fSyntaxColorList.getSelectionIndex();
				String key= fSyntaxColorListModel[i][1];
				
				PreferenceConverter.setValue(fOverlayStore, key, fSyntaxForegroundColorEditor.getColorValue());
			}
		});
		fBackgroundColorButton.addSelectionListener(new SelectionListener() {