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
switch (index) {
		case LEFT_TOP:
			data.left = new FormAttachment(0, 0);
			data.top = new FormAttachment(0, 0);
			return data;
		case LEFT_BOTTOM:
			data.left = new FormAttachment(0, 0);
			data.bottom = new FormAttachment(100, 0);
			return data;
		case RIGHT_TOP:
			data.right = new FormAttachment(100, 0);
			data.top = new FormAttachment(0, 0);
			return data;
		case RIGHT_BOTTOM:
			data.right = new FormAttachment(100, 0);
			data.bottom = new FormAttachment(100, 0);
			return data;
		}
		
		return data;
	}
	/**
	 * Show the specified text using the same hover dialog as is used to show
	 * decorator descriptions. Normally, a decoration's description text will be
	 * shown in an info hover over the field's control whenever the mouse hovers
	 * over the decoration. This method can be used to show a decoration's
	 * description text at other times (such as when the control receives
	 * focus), or to show other text associated with the field.
	 * 
	 * <p>