From 0dd34d197ed08d998e964f5ecc6fd8e55d9d6876 Mon Sep 17 00:00:00 2001
From: Jon Evans <jon@craftyjon.com>
Date: Tue, 16 Jun 2020 19:59:00 -0400
Subject: [PATCH] Ensure currentGrid is valid on startup

Fixes https://gitlab.com/kicad/code/kicad/-/issues/4666
---
 common/tool/common_tools.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/common/tool/common_tools.cpp b/common/tool/common_tools.cpp
index 65109a5409..f8cb4d62ff 100644
--- a/common/tool/common_tools.cpp
+++ b/common/tool/common_tools.cpp
@@ -392,6 +392,8 @@ int COMMON_TOOLS::OnGridChanged()
 {
     int& currentGrid = m_toolMgr->GetSettings()->m_Window.grid.last_size_idx;
 
+    currentGrid = std::max( 0, std::min( currentGrid, static_cast<int>( m_grids.size() ) - 1 ) );
+
     // Update the combobox (if any)
     wxUpdateUIEvent dummy;
     m_frame->OnUpdateSelectGrid( dummy );