Bug 289599 [Preferences] PreferenceStore.setToDefault fires redundant PropertyChangeEvents
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceStore.java
if (value == null) {
			return DOUBLE_DEFAULT_DEFAULT;
		}
		double ival = DOUBLE_DEFAULT_DEFAULT;
		try {
			ival = new Double(value).doubleValue();
		} catch (NumberFormatException e) {
		}
		return ival;
	}
	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public float getFloat(String name) {
		return getFloat(properties, name);
	}
	/**
	 * Helper function: gets float for a given name.
	 * 
	 * @param p
	 * @param name
	 * @return float
	 */
	private float getFloat(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return FLOAT_DEFAULT_DEFAULT;
		}
		float ival = FLOAT_DEFAULT_DEFAULT;
		try {