diff --git a/imgui.cpp b/imgui.cpp
index 3663a46fa..0621e7324 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -3092,6 +3092,7 @@ ImGuiWindow::ImGuiWindow(ImGuiContext* context, const char* name) : DrawListInst
     DrawList = &DrawListInst;
     DrawList->_Data = &context->DrawListSharedData;
     DrawList->_OwnerName = Name;
+    IM_PLACEMENT_NEW(&WindowClass) ImGuiWindowClass();
 }
 
 ImGuiWindow::~ImGuiWindow()