From a4e95c500fd9bdbfa5d3eecfa6b1a99a2c65b768 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Mon, 14 Jul 2025 20:09:17 -0700
Subject: [PATCH] Prevent command line applications handling dark mode

Double-check before getting background color from invalid m_parent also

Fixes https://gitlab.com/kicad/code/kicad/-/issues/21317

(cherry picked from commit 9cb3a37b6f97b58fc1b29411bdc5a55d34603aee)
---
 common/widgets/grid_color_swatch_helpers.cpp | 2 +-
 pcbnew/pcb_base_edit_frame.cpp               | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/common/widgets/grid_color_swatch_helpers.cpp b/common/widgets/grid_color_swatch_helpers.cpp
index e683187eda..344493a3be 100644
--- a/common/widgets/grid_color_swatch_helpers.cpp
+++ b/common/widgets/grid_color_swatch_helpers.cpp
@@ -116,7 +116,7 @@ void GRID_CELL_COLOR_RENDERER::Draw( wxGrid& aGrid, wxGridCellAttr& aAttr, wxDC&
 
 void GRID_CELL_COLOR_RENDERER::OnDarkModeToggle()
 {
-    m_checkerboardBg = m_parent->GetBackgroundColour();
+    m_checkerboardBg = m_parent ? m_parent->GetBackgroundColour() : wxSystemSettings::GetColour( wxSYS_COLOUR_WINDOW );
 }
 
 
diff --git a/pcbnew/pcb_base_edit_frame.cpp b/pcbnew/pcb_base_edit_frame.cpp
index 04704fe7b3..b07d5ab932 100644
--- a/pcbnew/pcb_base_edit_frame.cpp
+++ b/pcbnew/pcb_base_edit_frame.cpp
@@ -60,6 +60,10 @@ PCB_BASE_EDIT_FRAME::PCB_BASE_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent,
 {
     m_darkMode = KIPLATFORM::UI::IsDarkTheme();
 
+    // Do not register the idle event handler if we are running in headless mode.
+    if( !wxApp::GetGUIInstance() )
+        return;
+
     Bind( wxEVT_IDLE,
           [this]( wxIdleEvent& aEvent )
           {