Bug 124202 [Field Assist] - decorated fields should not size the created control
The philosophy of DecoratedField is that the client creates the target control and accesses it with normal SWT coding. The decorated field manages the decorations but otherwise statys out of the way. This philosophy is violated when DecoratedField sets the width of the field to IDialogConstants.ENTRY_WIDTH. Sizing decisions should be made by the client of the decorated field, not the field itself.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/DecoratedField.java
*            shown when the field has focus.
		 */
		FieldDecorationData(FieldDecoration decoration, Label label,
				FormData formData, boolean showOnFocus) {
			this.decoration = decoration;
			this.label = label;
			this.data = formData;
			this.showOnFocus = showOnFocus;
		}
	}
	/**
	 * Decorations keyed by position.
	 */
	private FieldDecorationData[] decDatas = new FieldDecorationData[DECORATION_SLOTS];
	/**
	 * The associated control
	 */
	private Control control;
	/**
	 * The composite with form layout used to manage decorations.
	 */
	private Composite form;
	/**
	 * The hover used for showing description text
	 */
	private Hover hover;
	/**
	 * The hover used to show a decoration image's description.
	 */
	class Hover {