composite.setLayout(FieldAssistUtils.createGridLayout());
composite.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
ContentAssistField field = new ContentAssistField(composite, SWT.BORDER,
new TextControlCreator(), new TextContentAdapter(),
new TypeNameContentProposalProvider(project, packageName),
ITextEditorActionDefinitionIds.CONTENT_ASSIST_PROPOSALS,
new char[0]);
final Text text = (Text) field.getControl();
field.getLayoutControl().setLayoutData(new GridData(GridData.FILL_HORIZONTAL));