Examples: Win32: Using IsChild() to be compatible with windows created within a parent. (#1951, #2087, #2156, #2232)

docs/CHANGELOG.txt

@@ -38,8 +38,8 @@ Other Changes:
 - ImDrawList: Fixed AddCircle(), AddCircleFilled() angle step being off, which was visible when drawing a "circle"
   with a small number of segments (e.g. an hexagon). (#2287) [@baktery]
 - Fonts: imgui_freetype: Added support for imgui allocators + custom FreeType only SetAllocatorFunctions. (#2285) [@Vuhdo]
-- Examples: Win32: Using GetForegroundWindow() instead of GetActiveWindow() to be compatible with windows created 
-  in a different thread. (#1951, #2087, #2156, #2232) [many people]
+- Examples: Win32: Using GetForegroundWindow()+IsChild() instead of GetActiveWindow() to be compatible with windows created 
+  in a different thread or parent. (#1951, #2087, #2156, #2232) [many people]
 - Examples: Win32: Added support for XInput games (if ImGuiConfigFlags_NavEnableGamepad is enabled).
 - Examples: DirectX9: Explicitly disable fog (D3DRS_FOGENABLE) before drawing in case user state has it set. (#2288, #2230)
 

examples/imgui_impl_win32.cpp

@@ -18,7 +18,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2019-01-15: Inputs: Using GetForegroundWindow() instead of GetActiveWindow() to be compatible with windows created in a different thread.
+//  2019-01-17: Inputs: Using GetForegroundWindow()+IsChild() instead of GetActiveWindow() to be compatible with windows created in a different thread or parent.
 //  2019-01-15: Inputs: Added support for XInput gamepads (if ImGuiConfigFlags_NavEnableGamepad is set by user application).
 //  2018-11-30: Misc: Setting up io.BackendPlatformName so it can be displayed in the About Window.
 //  2018-06-29: Inputs: Added support for the ImGuiMouseCursor_Hand cursor.
@@ -138,9 +138,10 @@ static void ImGui_ImplWin32_UpdateMousePos()
     // Set mouse position
     io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
     POINT pos;
-    if (::GetForegroundWindow() == g_hWnd && ::GetCursorPos(&pos))
-        if (::ScreenToClient(g_hWnd, &pos))
-            io.MousePos = ImVec2((float)pos.x, (float)pos.y);
+    if (HWND active_window = ::GetForegroundWindow())
+        if (active_window == g_hWnd || ::IsChild(active_window, g_hWnd))
+            if (::GetCursorPos(&pos) && ::ScreenToClient(g_hWnd, &pos))
+                io.MousePos = ImVec2((float)pos.x, (float)pos.y);
 }
 
 #ifdef _MSC_VER