Internals: Popup: Separating MousePosOnOpen and PopupPosOnOpen. They are equal in the master branch but different in the navigation branch.

imgui.cpp

@@ -3725,7 +3725,9 @@ void ImGui::OpenPopupEx(ImGuiID id, bool reopen_existing)
     ImGuiContext& g = *GImGui;
     ImGuiWindow* parent_window = g.CurrentWindow;
     int current_stack_size = g.CurrentPopupStack.Size;
-    ImGuiPopupRef popup_ref = ImGuiPopupRef(id, parent_window, parent_window->GetID("##Menus"), g.IO.MousePos); // Tagged as new ref because constructor sets Window to NULL.
+    ImVec2 mouse_pos = g.IO.MousePos;
+    ImVec2 popup_pos = mouse_pos; // NB: In the Navigation branch popup_pos may not use mouse_pos.
+    ImGuiPopupRef popup_ref = ImGuiPopupRef(id, parent_window, parent_window->GetID("##Menus"), popup_pos, mouse_pos); // Tagged as new ref because constructor sets Window to NULL.
     if (g.OpenPopupStack.Size < current_stack_size + 1)
         g.OpenPopupStack.push_back(popup_ref);
     else if (reopen_existing || g.OpenPopupStack[current_stack_size].PopupId != id)
@@ -4479,7 +4481,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             // 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->PosFloat = g.IO.MousePos;
+                window->PosFloat = g.CurrentPopupStack.back().PopupPosOnOpen;
         }
 
         // Collapse window by double-clicking on title bar

imgui_internal.h

@@ -401,9 +401,10 @@ struct ImGuiPopupRef
     ImGuiWindow*        Window;         // Resolved on BeginPopup() - may stay unresolved if user never calls OpenPopup()
     ImGuiWindow*        ParentWindow;   // Set on OpenPopup()
     ImGuiID             ParentMenuSet;  // Set on OpenPopup()
+    ImVec2              PopupPosOnOpen; // Preferred popup position (typically == MousePosOnOpen when using mouse)
     ImVec2              MousePosOnOpen; // Copy of mouse position at the time of opening popup
 
-    ImGuiPopupRef(ImGuiID id, ImGuiWindow* parent_window, ImGuiID parent_menu_set, const ImVec2& mouse_pos) { PopupId = id; Window = NULL; ParentWindow = parent_window; ParentMenuSet = parent_menu_set; MousePosOnOpen = mouse_pos; }
+    ImGuiPopupRef(ImGuiID id, ImGuiWindow* parent_window, ImGuiID parent_menu_set, const ImVec2& popup_pos, const ImVec2& mouse_pos) { PopupId = id; Window = NULL; ParentWindow = parent_window; ParentMenuSet = parent_menu_set; PopupPosOnOpen = popup_pos; MousePosOnOpen = mouse_pos; }
 };
 
 struct ImGuiColumnData