Bug 127289 [Markers] SystemFilter and group selection state not preserved
We are not preserving the selection state of the system filters or which group is selected.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerFilter.java
*            </ul>
	 */
	void setOnResource(int onResource) {
		if (onResource >= ON_ANY && onResource <= ON_WORKING_SET) {
			this.onResource = onResource;
		}
	}
	/**
	 * @return the selected resource(s) withing the workbench.
	 */
	IResource[] getFocusResource() {
		return focusResource;
	}
	/**
	 * Sets the focused resources.
	 */
	public void setFocusResource(IResource[] resources) {
		focusResource = resources;
	}
	/**
	 * @return
	 * <ul>
	 * <li><code>true</code> if the filter is enabled.</li>
	 * <li><code>false</code> if the filter is not enabled.</li>
	 * </ul>
	 */
	public boolean isEnabled() {
		return enabled;
	}
	/**