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
* @param decoration
	 *            A FieldDecoration describing the image and description for the
	 *            decoration
	 * 
	 * @param position
	 *            The SWT constant indicating the position of the decoration
	 *            relative to the field's control. The position should include
	 *            style bits describing both the vertical and horizontal
	 *            orientation. <code>SWT.LEFT</code> and
	 *            <code>SWT.RIGHT</code> describe the horizontal placement of
	 *            the decoration relative to the field, and the constants
	 *            <code>SWT.TOP</code> and <code>SWT.BOTTOM</code> describe
	 *            the vertical alignment of the decoration relative to the
	 *            field. Decorations always appear on either horizontal side of
	 *            the field, never above or below it. For example, a decoration
	 *            appearing on the left side of the field, at the top, is
	 *            specified as SWT.LEFT | SWT.TOP. If an image decoration
	 *            already exists in the specified position, it will be replaced
	 *            by the one specified.
	 * @param showOnFocus
	 *            <code>true</code> if the decoration should only be shown
	 *            when the associated control has focus, <code>false</code> if
	 *            it should always be shown.
	 * 
	 */
	public void addFieldDecoration(FieldDecoration decoration, int position,
			boolean showOnFocus) {
		final Label label;
		FormData formData;
		int i = indexForPosition(position);