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
private static final String EMPTY = ""; 
		/**
		 * Offset of info hover arrow from the left or right side.
		 */
		private int hao = 10;
		/**
		 * Width of info hover arrow.
		 */
		private int haw = 8;
		/**
		 * Height of info hover arrow.
		 */
		private int hah = 10;
		/**
		 * Margin around info hover text.
		 */
		private int hm = 2;
		/**
		 * This info hover's shell.