Begin: Shuffling bits of code around.

imgui.cpp

@@ -4565,14 +4565,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_AlwaysUseWindowPadding | ImGuiWindowFlags_Popup)) && window->WindowBorderSize == 0.0f)
             window->WindowPadding = ImVec2(0.0f, (flags & ImGuiWindowFlags_MenuBar) ? style.WindowPadding.y : 0.0f);
 
-        if (window_just_activated_by_user)
-        {
-            // Popup first latch mouse position, will position itself when it appears next frame
-            window->AutoPosLastDirection = ImGuiDir_None;
-            if ((flags & ImGuiWindowFlags_Popup) != 0 && !window_pos_set_by_api)
-                window->Pos = window->PosFloat = g.CurrentPopupStack.back().OpenPopupPos;
-        }
-
         // Collapse window by double-clicking on title bar
         // At this point we don't have a clipping rectangle setup yet, so we can use the title bar area for hit detection and drawing
         if (!(flags & ImGuiWindowFlags_NoTitleBar) && !(flags & ImGuiWindowFlags_NoCollapse))
@@ -4660,14 +4652,23 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
         // POSITION
 
+        // Popup latch its initial position, will position itself when it appears next frame
+        if (window_just_activated_by_user)
+        {
+            window->AutoPosLastDirection = ImGuiDir_None;
+            if ((flags & ImGuiWindowFlags_Popup) != 0 && !window_pos_set_by_api)
+                window->Pos = window->PosFloat = g.CurrentPopupStack.back().OpenPopupPos;
+        }
+
         // Position child window
         if (flags & ImGuiWindowFlags_ChildWindow)
         {
             window->BeginOrderWithinParent = parent_window->DC.ChildWindows.Size;
             parent_window->DC.ChildWindows.push_back(window);
+
+            if (!(flags & ImGuiWindowFlags_Popup) && !window_pos_set_by_api)
+                window->Pos = window->PosFloat = parent_window->DC.CursorPos;
         }
-        if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & ImGuiWindowFlags_Popup) && !window_pos_set_by_api)
-            window->Pos = window->PosFloat = parent_window->DC.CursorPos;
 
         const bool window_pos_with_pivot = (window->SetWindowPosVal.x != FLT_MAX && window->HiddenFrames == 0);
         if (window_pos_with_pivot)