From 8fc25800e0f4164c6edc4e9b00cc0e8d988d3b3c Mon Sep 17 00:00:00 2001
From: ocornut <omar@miracleworld.net>
Date: Thu, 2 Jul 2026 15:02:59 +0200
Subject: [PATCH] Fonts, Context: assert that ImFontAtlas has no other
 references when destroying an owned atlas. (#9426)

---
 docs/CHANGELOG.txt |  1 +
 imgui.cpp          | 10 +++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 1119b7ab6..aca07b0ad 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -95,6 +95,7 @@ Other Changes:
     calling ClearFonts() during rendering.
   - Fixed an issue where passing a manually created ImFontAtlas to CreateContext() would
     incorrectly destroy it in DestroyContext() when ref-count gets back to zero. (#9426)
+  - Destroying an ImGui context using a ImFontAtlas checks that the later has no references.
 - Nav:
   - Fixed context menu activation with gamepad erroneously testing for _NavEnableKeyboard
     instead of _NavEnableGamepad. (#9454, #8803, #9270) [@Clownacy]
diff --git a/imgui.cpp b/imgui.cpp
index a7d03caa4..2feefc854 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -4495,10 +4495,14 @@ void ImGui::Shutdown()
     for (ImFontAtlas* atlas : g.FontAtlases)
     {
         UnregisterFontAtlas(atlas);
-        if (atlas->RefCount == 0 && atlas->OwnerContext == &g)
+        if (atlas->OwnerContext == &g)
         {
-            atlas->Locked = false;
-            IM_DELETE(atlas);
+            IM_ASSERT(atlas->RefCount == 0 && "Destroying context owning a ImFontAtlas which is still used elsewhere!");
+            if (atlas->RefCount == 0)
+            {
+                atlas->Locked = false;
+                IM_DELETE(atlas);
+            }
         }
     }
     g.DrawListSharedData.TempBuffer.clear();