Nav: fixed a bug where GamepadMenu couldn't toggle between main and menu layer while navigating a Modal window. (#8834)

Amend 901d432cb but for Gamepad.

docs/CHANGELOG.txt

@@ -70,6 +70,8 @@ Other Changes:
   any potential shrinking is applied.
 - Tabs: fixed tab bar underline not drawing below scroll buttons, when
   they are enabled (minor regression from 1.90). (#6820, #4859, #5022, #5239)
+- Nav: fixed a bug where GamepadMenu button couldn't toggle between main and
+  menu layers while navigating a Modal window. (#8834)
 - Error Handling: minor improvements to error handling for TableGetSortSpecs()
   and TableSetBgColor() calls. (#1651, #8499)
 - Misc: fixed building with IMGUI_DISABLE_DEBUG_TOOLS only. (#8796)

imgui.cpp

@@ -14200,9 +14200,16 @@ static void ImGui::NavUpdateWindowing()
     const bool nav_keyboard_active = (io.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard) != 0;
     const bool keyboard_next_window = allow_windowing && g.ConfigNavWindowingKeyNext && Shortcut(g.ConfigNavWindowingKeyNext, ImGuiInputFlags_Repeat | ImGuiInputFlags_RouteAlways, owner_id);
     const bool keyboard_prev_window = allow_windowing && g.ConfigNavWindowingKeyPrev && Shortcut(g.ConfigNavWindowingKeyPrev, ImGuiInputFlags_Repeat | ImGuiInputFlags_RouteAlways, owner_id);
-    const bool start_windowing_with_gamepad = allow_windowing && nav_gamepad_active && !g.NavWindowingTarget && Shortcut(ImGuiKey_NavGamepadMenu, ImGuiInputFlags_RouteAlways, owner_id);
+    const bool start_toggling_with_gamepad = nav_gamepad_active && !g.NavWindowingTarget && Shortcut(ImGuiKey_NavGamepadMenu, ImGuiInputFlags_RouteAlways, owner_id);
+    const bool start_windowing_with_gamepad = allow_windowing && start_toggling_with_gamepad;
     const bool start_windowing_with_keyboard = allow_windowing && !g.NavWindowingTarget && (keyboard_next_window || keyboard_prev_window); // Note: enabled even without NavEnableKeyboard!
     bool just_started_windowing_from_null_focus = false;
+    if (start_toggling_with_gamepad)
+    {
+        g.NavWindowingToggleLayer = true; // Gamepad starts toggling layer
+        g.NavWindowingToggleKey = ImGuiKey_NavGamepadMenu;
+        g.NavWindowingInputSource = g.NavInputSource = ImGuiInputSource_Gamepad;
+    }
     if (start_windowing_with_gamepad || start_windowing_with_keyboard)
         if (ImGuiWindow* window = g.NavWindow ? g.NavWindow : FindWindowNavFocusable(g.WindowsFocusOrder.Size - 1, -INT_MAX, -1))
         {
@@ -14210,7 +14217,6 @@ static void ImGui::NavUpdateWindowing()
                 g.NavWindowingTarget = g.NavWindowingTargetAnim = window->RootWindow; // Current location
             g.NavWindowingTimer = g.NavWindowingHighlightAlpha = 0.0f;
             g.NavWindowingAccumDeltaPos = g.NavWindowingAccumDeltaSize = ImVec2(0.0f, 0.0f);
-            g.NavWindowingToggleLayer = start_windowing_with_gamepad ? true : false; // Gamepad starts toggling layer
             g.NavWindowingInputSource = g.NavInputSource = start_windowing_with_keyboard ? ImGuiInputSource_Keyboard : ImGuiInputSource_Gamepad;
             if (g.NavWindow == NULL)
                 just_started_windowing_from_null_focus = true;

imgui_internal.h

@@ -2328,8 +2328,8 @@ struct ImGuiContext
     float                   NavWindowingTimer;
     float                   NavWindowingHighlightAlpha;
     ImGuiInputSource        NavWindowingInputSource;
-    bool                    NavWindowingToggleLayer;
-    ImGuiKey                NavWindowingToggleKey;
+    bool                    NavWindowingToggleLayer;            // Set while Alt or GamepadMenu is held, may be cleared by other operations, and processed when releasing the key.
+    ImGuiKey                NavWindowingToggleKey;              // Keyboard/gamepad key used when toggling to menu layer.
     ImVec2                  NavWindowingAccumDeltaPos;
     ImVec2                  NavWindowingAccumDeltaSize;