TreeNode: Fixed nodes with ImGuiTreeNodeFlags_Leaf flag always returning true which was meaningless. Tweak demo.

imgui.cpp

@@ -8109,7 +8109,7 @@ void ImGui::LogButtons()
 bool ImGui::TreeNodeBehaviorIsOpen(ImGuiID id, ImGuiTreeNodeFlags flags)
 {
     if (flags & ImGuiTreeNodeFlags_Leaf)
-        return true;
+        return false;
 
     // We only write to the tree storage if the user clicks (or explicitly use SetNextTreeNode*** functions)
     ImGuiContext& g = *GImGui;