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
}
	/*
	 * Get the FieldDecorationData that corresponds to the given decoration.
	 */
	private FieldDecorationData getDecorationData(FieldDecoration dec) {
		for (int i = 0; i < DECORATION_SLOTS; i++) {
			if (decDatas[i] != null && dec == decDatas[i].decoration
					&& decDatas[i].label != null
					&& !decDatas[i].label.isDisposed())
				return decDatas[i];
		}
		return null;
	}
	/*
	 * Show the specified text in the hover, positioning the hover near the
	 * specified control.
	 */
	private void showHoverText(String text, Control hoverNear) {
		if (text == null) {
			hideHover();
			return;
		}
		if (hover == null) {
			hover = new Hover(hoverNear.getShell());
		}
		hover.setText(text, hoverNear, control);
		hover.setVisible(true);
	}
}