From b0d544659149f5343b2f002d57ff51f35e3be6e4 Mon Sep 17 00:00:00 2001
From: Marius PvW <marius@taniustech.com>
Date: Wed, 4 Nov 2026 10:23:56 -0500
Subject: [PATCH] Backends: SDL2: create tooltip and popup viewports with
 SDL_WINDOW_TOOLTIP / SDL_WINDOW_POPUP_MENU. Fallback for sdl2-compat. (#7950)

---
 backends/imgui_impl_sdl2.cpp | 26 ++++++++++++++++++++++++++
 docs/CHANGELOG.txt           |  4 ++++
 2 files changed, 30 insertions(+)

diff --git a/backends/imgui_impl_sdl2.cpp b/backends/imgui_impl_sdl2.cpp
index bcc3b8595..3b407b504 100644
--- a/backends/imgui_impl_sdl2.cpp
+++ b/backends/imgui_impl_sdl2.cpp
@@ -26,6 +26,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2026-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2026-11-04: [Docking] Create tooltip and popup viewports with SDL_WINDOW_TOOLTIP / SDL_WINDOW_POPUP_MENU so they do not steal focus and stack above always-on-top windows. Fall back to an always-on-top window when creation fails (sdl2-compat). (#7950)
 //  2026-08-06: Fixed querying framebuffer scale when using Metal. (#5592)
 //  2026-07-15: Inputs: restore SDL_StartTextInput()/SDL_StopTextInput() in IME handler for on-screen keyboard support on Android/mobile. (#7636, #9474)
 //  2026-04-16: Made ImGui_ImplSDL2_GetContentScaleForWindow(), ImGui_ImplSDL2_GetContentScaleForDisplay() helpers return a minimum of 1.0f, as some Linux setup seems to report <1.0f value and this breaks scaling border size. (#9369)
@@ -1152,7 +1153,32 @@ static void ImGui_ImplSDL2_CreateWindow(ImGuiViewport* viewport)
 #if SDL_HAS_ALWAYS_ON_TOP
     sdl_flags |= (viewport->Flags & ImGuiViewportFlags_TopMost) ? SDL_WINDOW_ALWAYS_ON_TOP : 0;
 #endif
+
+    // Viewports for short-lived floating windows (tooltips, popups, menus) carry _NoTaskBarIcon + _NoDecoration
+    // + _NoFocusOnAppearing + _NoFocusOnClick, and among those only tooltips also carry _TopMost + _NoInputs
+    // (see ImGui::WindowSelectViewport()). Create them with the corresponding SDL window type:
+    // SDL_WINDOW_TOOLTIP windows never receive input focus, and SDL_WINDOW_POPUP_MENU windows stack above
+    // SDL_WINDOW_ALWAYS_ON_TOP windows.
+    if ((viewport->Flags & ImGuiViewportFlags_NoFocusOnClick) && (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+        && (viewport->Flags & ImGuiViewportFlags_NoDecoration) && (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon))
+    {
+        if ((viewport->Flags & ImGuiViewportFlags_NoInputs) && (viewport->Flags & ImGuiViewportFlags_TopMost))
+            sdl_flags |= SDL_WINDOW_TOOLTIP;
+        else
+            sdl_flags |= SDL_WINDOW_POPUP_MENU;
+    }
+
     vd->Window = SDL_CreateWindow("No Title Yet", (int)viewport->Pos.x, (int)viewport->Pos.y, (int)viewport->Size.x, (int)viewport->Size.y, sdl_flags);
+    if (vd->Window == nullptr && (sdl_flags & (SDL_WINDOW_TOOLTIP | SDL_WINDOW_POPUP_MENU)))
+    {
+        // sdl2-compat maps tooltip/popup-menu windows onto SDL3 popups, which require a parent window
+        // and therefore fail in SDL_CreateWindow(); approximate with an always-on-top window.
+        sdl_flags &= ~(SDL_WINDOW_TOOLTIP | SDL_WINDOW_POPUP_MENU);
+#if SDL_HAS_ALWAYS_ON_TOP
+        sdl_flags |= SDL_WINDOW_ALWAYS_ON_TOP;
+#endif
+        vd->Window = SDL_CreateWindow("No Title Yet", (int)viewport->Pos.x, (int)viewport->Pos.y, (int)viewport->Size.x, (int)viewport->Size.y, sdl_flags);
+    }
     vd->WindowOwned = true;
     if (use_opengl)
     {
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index b5b7ecbaa..aa8e9d0d7 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -114,6 +114,10 @@ Docking+Viewports Branch:
   - Win32: make windows appear with `::SetWindowPos()` w/ `SWP_NOOWNERZORDER` instead
     of unparenting + `ShowWindow()`. Fixes missing taskbar icon for newly appearing
     windows that are parented and use `ImGuiViewportFlags_NoFocusOnAppearing`. (#7354, #8669)
+  - SDL2: create tooltip and popup/menu viewports with `SDL_WINDOW_TOOLTIP` and
+    `SDL_WINDOW_POPUP_MENU`, so they no longer take focus from the parent window and
+    stack above `SDL_WINDOW_ALWAYS_ON_TOP` windows. Falls back to an always-on-top
+    window when creation fails (sdl2-compat requires a parent for those). (#7950)