diff --git a/imgui.cpp b/imgui.cpp
index 9935c78..f5ce8d6 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -2038,6 +2038,7 @@
 {
     ImGuiState& g = GImGui;
     const ImGuiStyle& style = g.Style;
+    IM_ASSERT(g.Initialized);                       // Forgot to call ImGui::NewFrame()
 
     ImGuiWindow* window = FindWindow(name);
     if (!window)