diff --git a/docs/sdk/scenario/scenario.xml b/docs/sdk/scenario/scenario.xml
index 5c4bceff4..755b7cde1 100644
--- a/docs/sdk/scenario/scenario.xml
+++ b/docs/sdk/scenario/scenario.xml
@@ -248,7 +248,7 @@
       <row>
         <literal_col>AutoScanSideOpen</literal_col>
         <col>Integer</col>
-        <col>0 or 1. If 1, the left and right borders are closed if the corresponding map pixel in the left or right row has tunnel background and open otherwise.</col>
+        <col>0, 1, or 2. If 1, the left and right borders are closed if the corresponding map pixel in the left or right row has non-sky foreground or background and open otherwise. If 2, it only checks the background.</col>
       </row>
       <row>
         <literal_col>MapWidth</literal_col>
diff --git a/src/landscape/C4Landscape.cpp b/src/landscape/C4Landscape.cpp
index aafdc0639..a119eba06 100644
--- a/src/landscape/C4Landscape.cpp
+++ b/src/landscape/C4Landscape.cpp
@@ -2072,14 +2072,19 @@ bool C4Landscape::P::InitBorderPix()
 
 	if (Game.C4S.Landscape.AutoScanSideOpen)
 	{
+		// Compatibility: check both foreground and background material per
+		// default, Top/BottomOpen=2-like behavior with AutoScanSideOpen=2.
+		bool only_bg = Game.C4S.Landscape.AutoScanSideOpen == 2;
 		LeftColPix.resize(Height);
 		RightColPix.resize(Height);
 		uint8_t map_pix;
 		for (int32_t y = 0; y < Height; ++y)
 		{
 			map_pix = MapBkg->GetPix(0, y / MapZoom);
+			if (!only_bg) map_pix += Map->GetPix(0, y / MapZoom);
 			LeftColPix[y] = ((map_pix != 0) ? MCVehic : 0);
 			map_pix = MapBkg->GetPix(Map->Wdt - 1, y / MapZoom);
+			if (!only_bg) map_pix += Map->GetPix(Map->Wdt - 1, y / MapZoom);
 			RightColPix[y] = ((map_pix != 0) ? MCVehic : 0);
 		}
 	}