diff --git a/doc/fixes37.0 b/doc/fixes37.0
index 49b7bd2db..dec38a215 100644
--- a/doc/fixes37.0
+++ b/doc/fixes37.0
@@ -161,6 +161,8 @@ fix door created into random wall or position opening into solid wall
 	being more general; change its default to True
 X11: was still initializing map to 'stone' instead of 'unexplored' after they
 	became separate glyphs
+X11: for text map without color, add support for black&white ice; draw it in
+	inverse video to distinguish from ordinary floor
 
 
 Platform- and/or Interface-Specific Fixes
diff --git a/win/X11/winX.c b/win/X11/winX.c
index feab64a44..de4849ab7 100644
--- a/win/X11/winX.c
+++ b/win/X11/winX.c
@@ -98,7 +98,7 @@ static XtSignalId X11_sig_id;
 /* Interface definition, for windows.c */
 struct window_procs X11_procs = {
     "X11",
-    ( WC_COLOR | WC_HILITE_PET | WC_ASCII_MAP | WC_TILED_MAP
+    ( WC_COLOR | WC_INVERSE | WC_HILITE_PET | WC_ASCII_MAP | WC_TILED_MAP
      | WC_PLAYER_SELECTION | WC_PERM_INVENT | WC_MOUSE_SUPPORT ),
     /* status requires VIA_WINDOWPORT(); WC2_FLUSH_STATUS ensures that */
     ( WC2_FLUSH_STATUS
diff --git a/win/X11/winmap.c b/win/X11/winmap.c
index 74cfb4643..2d40dd6e5 100644
--- a/win/X11/winmap.c
+++ b/win/X11/winmap.c
@@ -129,7 +129,8 @@ int bkglyph UNUSED;
         co_ptr = &map_info->text_map.colors[y][x];
         colordif = (((special & MG_PET) != 0 && iflags.hilite_pet)
                     || ((special & MG_OBJPILE) != 0 && iflags.hilite_pile)
-                    || ((special & (MG_DETECT | MG_BW_LAVA)) != 0))
+                    || ((special & (MG_DETECT | MG_BW_LAVA | MG_BW_ICE)) != 0
+                        && iflags.use_inverse))
                       ? CLR_MAX : 0;
         if (*co_ptr != (uchar) (color + colordif)) {
             *co_ptr = (uchar) (color + colordif);
@@ -141,9 +142,9 @@ int bkglyph UNUSED;
 
     if (update_bbox) { /* update row bbox */
         if ((uchar) x < map_info->t_start[y])
-            map_info->t_start[y] = x;
+            map_info->t_start[y] = (uchar) x;
         if ((uchar) x > map_info->t_stop[y])
-            map_info->t_stop[y] = x;
+            map_info->t_stop[y] = (uchar) x;
     }
 }