Composite extensionsComposite = new Composite(pageComposite, SWT.FILL);
extensionsComposite.setLayout(pageLayout);
extensionsComposite.setLayoutData(new GridData(GridData.FILL,GridData.CENTER,true,false,2,1));
extensionEditor = new StringButtonFieldEditor(PreferenceConstants.P_SEARCH_EXTENSIONS, "", extensionsComposite) {
protected String changePressed() {
String exts = this.getStringValue();
exts = exts.replace(" ", "");
List<String> extList = Arrays.asList(exts.split(","));