+// The vista tree control includes some new code that originally broke the
+// multi-selection tree, causing seemingly spurious item selection state changes
+// during Shift or Ctrl-click item selection. (To witness the original broken
+// behavior, simply make IsLocked() below always return false). This problem was
+// solved by using the following class to 'unlock' an item's selection state.
+
+class TreeItemUnlocker
+{
+public:
+ // unlock a single item
+ TreeItemUnlocker(HTREEITEM item) { ms_unlockedItem = item; }
+
+ // unlock all items, don't use unless absolutely necessary
+ TreeItemUnlocker() { ms_unlockedItem = (HTREEITEM)-1; }
+
+ // lock everything back
+ ~TreeItemUnlocker() { ms_unlockedItem = NULL; }
+
+
+ // check if the item state is currently locked
+ static bool IsLocked(HTREEITEM item)
+ { return ms_unlockedItem != (HTREEITEM)-1 && item != ms_unlockedItem; }
+
+private:
+ static HTREEITEM ms_unlockedItem;
+};
+
+HTREEITEM TreeItemUnlocker::ms_unlockedItem = NULL;
+
+// ----------------------------------------------------------------------------
+// private functions
+// ----------------------------------------------------------------------------