Popups & Modals: fixed nested Begin() being erroneously input-inhibited. (useful for e.g. #718, #4461 and probably other things)

docs/CHANGELOG.txt

@@ -84,6 +84,9 @@ Breaking changes:
 
 Other Changes:
 
+- Popups & Modals: fixed nested Begin() being erroneously input-inhibited. While it is
+  unusual, you can nest a Begin() inside a popup or modal, it is occasionally useful to
+  achieve certains things (e.g. some ways to implement suggestion popup #718, #4461).
 - InputText: added experimental io.ConfigInputTextEnterKeepActive feature to make pressing
   Enter keep the input active and select all text.
 - InputText: numerical fields automatically accept full-width characters (U+FF01..U+FF5E)

imgui.cpp

@@ -3539,11 +3539,17 @@ static inline bool IsWindowContentHoverable(ImGuiWindow* window, ImGuiHoveredFla
             if (focused_root_window->WasActive && focused_root_window != window->RootWindow)
             {
                 // For the purpose of those flags we differentiate "standard popup" from "modal popup"
-                // NB: The order of those two tests is important because Modal windows are also Popups.
+                // NB: The 'else' is important because Modal windows are also Popups.
+                bool want_inhibit = false;
                 if (focused_root_window->Flags & ImGuiWindowFlags_Modal)
-                    return false;
-                if ((focused_root_window->Flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiHoveredFlags_AllowWhenBlockedByPopup))
-                    return false;
+                    want_inhibit = true;
+                else if ((focused_root_window->Flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiHoveredFlags_AllowWhenBlockedByPopup))
+                    want_inhibit = true;
+
+                // Inhibit hover unless the window is within the stack of our modal/popup
+                if (want_inhibit)
+                    if (!ImGui::IsWindowWithinBeginStackOf(window->RootWindow, focused_root_window))
+                        return false;
             }
     return true;
 }

imgui.h

@@ -23,7 +23,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM > 12345')
 #define IMGUI_VERSION               "1.89 WIP"
-#define IMGUI_VERSION_NUM           18819
+#define IMGUI_VERSION_NUM           18820
 #define IMGUI_HAS_TABLE
 
 /*