Bug 57762 [Dialogs] honor the platform button dismissal alignment on Mac and GTK
Button ordering is inverted on these platforms. See Display.getDismissalAlignment() or the equivalent JFace mechansim.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/OpenResourceDialog.java
/* (non-Javadoc)
	 * @see org.eclipse.ui.dialogs.FilteredItemsSelectionDialog#fillContextMenu(org.eclipse.jface.action.IMenuManager)
	 * @since 3.5
	 */
	protected void fillContextMenu(IMenuManager menuManager) {
		super.fillContextMenu(menuManager);
		IStructuredSelection selectedItems = getSelectedItems();
		if (selectedItems.isEmpty()) {
			return;
		}
		
		IWorkbenchPage activePage = getActivePage();
		if (activePage == null) {
			return;
		}
		
		OpenFileAction openFileAction = new OpenFileAction(activePage) {
			public void run() {
				okPressed();
			}
		};
		openFileAction.selectionChanged(selectedItems);
		if (!openFileAction.isEnabled()) {
			return;
		}
		menuManager.add(new Separator());
		menuManager.add(openFileAction);
		IAdaptable selectedAdaptable = getSelectedAdaptable();
		if (selectedAdaptable == null) {
			return;