Bug 189490 [CommonNavigator] Go To->Resource won't enable
I0524 1. Open the Project Explorer in the Resource perspective 2. Create a vanilla project P 3. Create a folder F 4. Create a file resource R Open the Navigate->Go To file. "Resource..." will remain disabled.
bundles/org.eclipse.ui.navigator.resources/src/org/eclipse/ui/internal/navigator/resources/actions/WorkingSetActionProvider.java
workingSet = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getAggregateWorkingSet();
		}
		if (workingSet != null) {
			workingSetFilter.setWorkingSet(workingSet);
			internalSetWorkingSet(workingSet);
			workingSetActionGroup.setWorkingSet(workingSet);
		}
    }
	/**
	 * Set current active working set.
	 *
	 * @param workingSet  working set to be activated, may be <code>null</code>
	 */
	protected void setWorkingSet(IWorkingSet workingSet) {
        internalSetWorkingSet(workingSet);
        workingSetFilter.setWorkingSet(emptyWorkingSet ? null : workingSet);
		if (viewer != null) {
			if (workingSet == null || emptyWorkingSet || !extensionStateModel.getBooleanProperty(WorkingSetsContentProvider.SHOW_TOP_LEVEL_WORKING_SETS)) {
				if (viewer.getInput() != originalViewerInput) {
					viewer.setInput(originalViewerInput);
				}
				if (!filterAdded) {
					viewer.addFilter(workingSetFilter);
					filterAdded = true;
				} else {
					viewer.refresh();
				}
			} else {
				viewer.removeFilter(workingSetFilter);
				filterAdded = false;