From 16ddc1698dc2d36b8054568477498cf32ae4117c Mon Sep 17 00:00:00 2001
From: ocornut <omarcornut@gmail.com>
Date: Thu, 24 Mar 2022 10:57:28 +0100
Subject: [PATCH] Fixed creating multiple-context (regression in 28ba54a).
 (#5135)

---
 imgui.cpp        | 30 ++++++++++++++----------------
 imgui.h          |  2 +-
 imgui_internal.h |  4 ++--
 3 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/imgui.cpp b/imgui.cpp
index 0949f4307..7ceb9e13e 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -3697,20 +3697,23 @@ void ImGui::GetAllocatorFunctions(ImGuiMemAllocFunc* p_alloc_func, ImGuiMemFreeF
 
 ImGuiContext* ImGui::CreateContext(ImFontAtlas* shared_font_atlas)
 {
+    ImGuiContext* prev_ctx = GetCurrentContext();
     ImGuiContext* ctx = IM_NEW(ImGuiContext)(shared_font_atlas);
-    if (GImGui == NULL)
-        SetCurrentContext(ctx);
-    Initialize(ctx);
+    SetCurrentContext(ctx);
+    Initialize();
+    if (prev_ctx != NULL)
+        SetCurrentContext(prev_ctx); // Restore previous context if any, else keep new one.
     return ctx;
 }
 
 void ImGui::DestroyContext(ImGuiContext* ctx)
 {
+    ImGuiContext* prev_ctx = GetCurrentContext();
     if (ctx == NULL)
-        ctx = GImGui;
-    Shutdown(ctx);
-    if (GImGui == ctx)
-        SetCurrentContext(NULL);
+        ctx = prev_ctx;
+    SetCurrentContext(ctx);
+    Shutdown();
+    SetCurrentContext((prev_ctx != ctx) ? prev_ctx : NULL);
     IM_DELETE(ctx);
 }
 
@@ -4464,9 +4467,9 @@ void ImGui::NewFrame()
     CallContextHooks(&g, ImGuiContextHookType_NewFramePost);
 }
 
-void ImGui::Initialize(ImGuiContext* context)
+void ImGui::Initialize()
 {
-    ImGuiContext& g = *context;
+    ImGuiContext& g = *GImGui;
     IM_ASSERT(!g.Initialized && !g.SettingsLoaded);
 
     // Add .ini handle for ImGuiWindow type
@@ -4496,10 +4499,10 @@ void ImGui::Initialize(ImGuiContext* context)
 }
 
 // This function is merely here to free heap allocations.
-void ImGui::Shutdown(ImGuiContext* context)
+void ImGui::Shutdown()
 {
     // The fonts atlas can be used prior to calling NewFrame(), so we clear it even if g.Initialized is FALSE (which would happen if we never called NewFrame)
-    ImGuiContext& g = *context;
+    ImGuiContext& g = *GImGui;
     if (g.IO.Fonts && g.FontAtlasOwnedByContext)
     {
         g.IO.Fonts->Locked = false;
@@ -4513,12 +4516,7 @@ void ImGui::Shutdown(ImGuiContext* context)
 
     // Save settings (unless we haven't attempted to load them: CreateContext/DestroyContext without a call to NewFrame shouldn't save an empty file)
     if (g.SettingsLoaded && g.IO.IniFilename != NULL)
-    {
-        ImGuiContext* backup_context = GImGui;
-        SetCurrentContext(&g);
         SaveIniSettingsToDisk(g.IO.IniFilename);
-        SetCurrentContext(backup_context);
-    }
 
     CallContextHooks(&g, ImGuiContextHookType_Shutdown);
 
diff --git a/imgui.h b/imgui.h
index f92c70dc6..6223fbcb2 100644
--- a/imgui.h
+++ b/imgui.h
@@ -65,7 +65,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.88 WIP"
-#define IMGUI_VERSION_NUM           18710
+#define IMGUI_VERSION_NUM           18711
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 
diff --git a/imgui_internal.h b/imgui_internal.h
index 8cf412ba1..b648bbc5f 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -2519,8 +2519,8 @@ namespace ImGui
     IMGUI_API ImDrawList*   GetForegroundDrawList(ImGuiViewport* viewport);                     // get foreground draw list for the given viewport. this draw list will be the last rendered one. Useful to quickly draw shapes/text over dear imgui contents.
 
     // Init
-    IMGUI_API void          Initialize(ImGuiContext* context);
-    IMGUI_API void          Shutdown(ImGuiContext* context);    // Since 1.60 this is a _private_ function. You can call DestroyContext() to destroy the context created by CreateContext().
+    IMGUI_API void          Initialize();
+    IMGUI_API void          Shutdown();    // Since 1.60 this is a _private_ function. You can call DestroyContext() to destroy the context created by CreateContext().
 
     // NewFrame
     IMGUI_API void          UpdateInputEvents(bool trickle_fast_inputs);