From 857bfbfb82a0ded4a6f9413afd53e9195aad5298 Mon Sep 17 00:00:00 2001
From: Clifford Garwood <cliff@cigii.com>
Date: Tue, 14 Apr 2026 09:17:23 -0400
Subject: [PATCH] fix: guard against empty option_set in OG_CustomCtrl
 widget-only lines

update_visibility() and render() both called front() on an empty vector
when a CtrlLine had no options (pure widget lines). Added an early-return
path in update_visibility() and a null-guard in render().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/slic3r/GUI/OG_CustomCtrl.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/OG_CustomCtrl.cpp b/src/slic3r/GUI/OG_CustomCtrl.cpp
index da4564f537..3eb3ac2edc 100644
--- a/src/slic3r/GUI/OG_CustomCtrl.cpp
+++ b/src/slic3r/GUI/OG_CustomCtrl.cpp
@@ -723,6 +723,19 @@ void OG_CustomCtrl::CtrlLine::update_visibility(ConfigOptionMode mode)
         return;
     const std::vector<Option>& option_set = og_line.get_options();
 
+    // Widget-only lines (no options appended) are always visible unless explicitly hidden.
+    if (option_set.empty()) {
+        is_visible = og_line.toggle_visible;
+        if (og_line.near_label_widget_win)
+            og_line.near_label_widget_win->Show(is_visible);
+        if (og_line.widget_sizer)
+            og_line.widget_sizer->ShowItems(is_visible);
+        if (og_line.extra_widget_sizer)
+            og_line.extra_widget_sizer->ShowItems(is_visible);
+        correct_items_positions();
+        return;
+    }
+
     const ConfigOptionMode& line_mode = option_set.front().opt.mode;
     is_visible = og_line.toggle_visible && line_mode <= mode;
 
@@ -773,7 +786,8 @@ void OG_CustomCtrl::CtrlLine::render(wxDC& dc, wxCoord h_pos, wxCoord v_pos)
         return;
     }
 
-    Field* field = ctrl->opt_group->get_field(og_line.get_options().front().opt_id);
+    Field* field = og_line.get_options().empty() ? nullptr :
+                   ctrl->opt_group->get_field(og_line.get_options().front().opt_id);
 
     bool suppress_hyperlinks = false;
     if (draw_just_act_buttons) {