diff --git a/src/utils/common/map_shared.cpp b/src/utils/common/map_shared.cpp
index e33e20cbf1..6c9329190b 100644
--- a/src/utils/common/map_shared.cpp
+++ b/src/utils/common/map_shared.cpp
@@ -29,6 +29,10 @@ ChunkFileResult_t LoadEntityKeyCallback(const char *szKey, const char *szValue,
 		{
 			pLoadEntity->nBaseContents = CONTENTS_DETAIL;
 		}
+		else if (!stricmp( szValue, "func_detail_nonsolid"))
+		{
+			pLoadEntity->nBaseContents = CONTENTS_DETAIL | CONTENTS_OPAQUE;
+		}
 		else if (!stricmp(szValue, "func_ladder"))
 		{
 			pLoadEntity->nBaseContents = CONTENTS_LADDER;
diff --git a/src/utils/vbsp/map.cpp b/src/utils/vbsp/map.cpp
index d39a2d7271..b133dc9226 100644
--- a/src/utils/vbsp/map.cpp
+++ b/src/utils/vbsp/map.cpp
@@ -1579,7 +1579,7 @@ ChunkFileResult_t CMapFile::LoadEntityCallback(CChunkFile *pFile, int nParam)
 		//
 		const char *pClassName = ValueForKey( mapent, "classname" );
 
-		if ( !strcmp( "func_detail", pClassName ) )
+		if ( !strcmp( "func_detail", pClassName ) || !strcmp( "func_detail_nonsolid", pClassName ) )
 		{
 			MoveBrushesToWorld (mapent);
 			mapent->numbrushes = 0;
@@ -2644,6 +2644,18 @@ bool LoadMapFile( const char *pszFileName )
 			AddPointToBounds (g_LoadingMap->mapbrushes[i].maxs, g_LoadingMap->map_mins, g_LoadingMap->map_maxs);
 		}
 
+		// CONTENTS_OPAQUE makes a brush not solid, but CONTENTS_WINDOW breaks its non-solidity
+		// CONTENTS_OPAQUE only gets applied via %compilenonsolid VMT property and func_detail_nonsolid entity
+		// %compilenonsolid prevents CONTENTS_WINDOW from being applied, func_detail_nonsolid does not, so we remove it here
+		for ( int i = 0; i < g_LoadingMap->entities[0].numbrushes; i++ )
+		{
+			mapbrush_t* brush = &g_LoadingMap->mapbrushes[i];
+			if ( ( brush->contents & CONTENTS_OPAQUE ) && ( brush->contents & CONTENTS_WINDOW ) )
+			{
+				brush->contents &= ~CONTENTS_WINDOW;
+			}
+		}
+
 		qprintf ("%5i brushes\n", g_LoadingMap->nummapbrushes);
 		qprintf ("%5i clipbrushes\n", g_LoadingMap->c_clipbrushes);
 		qprintf ("%5i total sides\n", g_LoadingMap->nummapbrushsides);