don't allow selection/context menu for empty row when no torrent in selected

macosx/FileOutlineView.m

@@ -48,7 +48,7 @@
     
     if (row >= 0)
     {
-        if (![self isRowSelected: row])
+        if ([self itemAtRow: row] && ![self isRowSelected: row])
             [self selectRowIndexes: [NSIndexSet indexSetWithIndex: row] byExtendingSelection: NO];
     }
     else

macosx/InfoWindowController.m

@@ -791,6 +791,11 @@
         return [outlineView rowHeight];
 }
 
+- (BOOL) outlineView: (NSOutlineView *) outlineView shouldSelectItem: (id) item
+{
+    return item != nil;
+}
+
 - (NSArray *) peerSortDescriptors
 {
     NSMutableArray * descriptors = [NSMutableArray array];