diff --git a/xwords4/common/board.c b/xwords4/common/board.c
index e365ea6c3..5e8642df3 100644
--- a/xwords4/common/board.c
+++ b/xwords4/common/board.c
@@ -1456,6 +1456,60 @@ board_invalRect( BoardCtxt* board, XP_Rect* rect )
     }
 } /* board_invalRect */
 
+#ifdef XWFEATURE_ACTIVERECT
+XP_Bool
+board_getActiveRect( const BoardCtxt* board, XP_Rect* rect )
+{
+    XP_Bool found = XP_FALSE;
+    XP_USE( rect );
+    XP_U16 minCol = 1000;
+    XP_U16 maxCol = 0;
+    XP_U16 minRow = 1000;
+    XP_U16 maxRow = 0;
+    const ModelCtxt* model = board->model;
+    XP_U16 nCols = model_numCols( board->model );
+    XP_S16 turn = board->selPlayer;
+    XP_U16 col, row;
+
+    for ( col = 0; col < nCols; ++col ) {
+        for ( row = 0; row < nCols; ++row ) {
+            if ( model_getTile( model, col, row, XP_TRUE, turn, NULL, NULL, 
+                                NULL, NULL ) ) {
+                found = XP_TRUE;
+                if ( row < minRow ) {
+                    minRow = row;
+                }
+                if ( row > maxRow ) {
+                    maxRow = row;
+                }
+                if ( col < minCol ) {
+                    minCol = col;
+                }
+                if ( col > maxCol ) {
+                    maxCol = col;
+                }
+            }
+        }
+    }
+
+    if ( !found ) {
+        minCol = maxCol = nCols / 2;
+        minRow = maxRow = nCols / 2;
+        found = XP_TRUE;
+    }
+
+    XP_Rect upperLeft, lowerRight;
+    getCellRect( board, minCol, minRow, &upperLeft );
+    getCellRect( board, maxCol, maxRow, &lowerRight );
+    rect->left = upperLeft.left;
+    rect->top = upperLeft.top;
+    rect->width = (lowerRight.left + lowerRight.width) - upperLeft.left;
+    rect->height = (lowerRight.top + lowerRight.height) - upperLeft.top;
+
+    return found;
+}
+#endif
+
 /* When the tray's hidden, check if it overlaps where the board wants to be,
  * and adjust the board's rect if needed so that hit-testing will work
  * "through" where the tray used to be.
diff --git a/xwords4/common/board.h b/xwords4/common/board.h
index 10de9e0a1..82591369c 100644
--- a/xwords4/common/board.h
+++ b/xwords4/common/board.h
@@ -96,6 +96,9 @@ void board_setTimerLoc( BoardCtxt* board,
                         XP_U16 timerWidth, XP_U16 timerHeight );
 void board_invalAll( BoardCtxt* board );
 void board_invalRect( BoardCtxt* board, XP_Rect* rect );
+#ifdef XWFEATURE_ACTIVERECT
+XP_Bool board_getActiveRect( const BoardCtxt* board, XP_Rect* rect );
+#endif
 
 XP_Bool board_draw( BoardCtxt* board );
 
@@ -119,6 +122,7 @@ BoardObjectType board_getFocusOwner( BoardCtxt* board );
 
 void board_hiliteCellAt( BoardCtxt* board, XP_U16 col, XP_U16 row );
 
+
 void board_resetEngine( BoardCtxt* board );
 
 XP_Bool board_commitTurn( BoardCtxt* board );
diff --git a/xwords4/linux/Makefile b/xwords4/linux/Makefile
index 74f954b65..89a838acd 100644
--- a/xwords4/linux/Makefile
+++ b/xwords4/linux/Makefile
@@ -113,6 +113,7 @@ DEFINES += -DXWFEATURE_HILITECELL
 DEFINES += -DXWFEATURE_CHANGEDICT
 DEFINES += -DXWFEATURE_DEVID
 DEFINES += -DXWFEATURE_COMMSACK
+#DEFINES += -DXWFEATURE_ACTIVERECT
 DEFINES += -DCOMMS_XPORT_FLAGSPROC
 DEFINES += -DINITIAL_CLIENT_VERS=2
 
diff --git a/xwords4/linux/gtkboard.c b/xwords4/linux/gtkboard.c
index 257449cd8..e180f228d 100644
--- a/xwords4/linux/gtkboard.c
+++ b/xwords4/linux/gtkboard.c
@@ -1071,6 +1071,28 @@ handle_memstats( GtkWidget* XP_UNUSED(widget), GtkGameGlobals* globals )
 } /* handle_memstats */
 #endif
 
+#ifdef XWFEATURE_ACTIVERECT
+static gint
+inval_board_ontimer( gpointer data )
+{
+    GtkGameGlobals* globals = (GtkGameGlobals*)data;
+    BoardCtxt* board = globals->cGlobals.game.board;
+    board_draw( board );
+    return XP_FALSE;
+} /* pen_timer_func */
+
+static void
+frame_active( GtkWidget* XP_UNUSED(widget), GtkGameGlobals* globals )
+{
+    XP_Rect rect;
+    BoardCtxt* board = globals->cGlobals.game.board;
+    board_getActiveRect( board, &rect );
+    frame_active_rect( globals->draw, &rect );
+    board_invalRect( board, &rect );
+    (void)g_timeout_add( 1000, inval_board_ontimer, globals );
+}
+#endif
+
 static GtkWidget*
 createAddItem( GtkWidget* parent, gchar* label, 
                GtkSignalFunc handlerFunc, GtkGameGlobals* globals ) 
@@ -1157,6 +1179,11 @@ makeMenus( GtkGameGlobals* globals )
                          GTK_SIGNAL_FUNC(handle_memstats), globals );
 #endif
 
+#ifdef XWFEATURE_ACTIVERECT
+    fileMenu = makeAddSubmenu( menubar, "Test" );
+    (void)createAddItem( fileMenu, "Frame active area", 
+                         GTK_SIGNAL_FUNC(frame_active), globals );
+#endif
     /*     (void)createAddItem( fileMenu, "Print board",  */
     /* 			 GTK_SIGNAL_FUNC(handle_print_board), globals ); */
 
diff --git a/xwords4/linux/gtkdraw.c b/xwords4/linux/gtkdraw.c
index dd350f42c..2d1942b49 100644
--- a/xwords4/linux/gtkdraw.c
+++ b/xwords4/linux/gtkdraw.c
@@ -1299,9 +1299,9 @@ allocAndSet( GdkColormap* map, GdkColor* color, unsigned short red,
     gboolean success = 
 #endif
         gdk_colormap_alloc_color( map,
-                                        color,
-                                        TRUE, /* writeable */
-                                        TRUE ); /* best-match */
+                                  color,
+                                  TRUE, /* writeable */
+                                  TRUE ); /* best-match */
     XP_ASSERT( success );
 } /* allocAndSet */
 
@@ -1440,5 +1440,11 @@ draw_gtk_status( GtkDrawCtx* dctx, char ch )
                     &dctx->black, NULL );
 }
 
+void
+frame_active_rect( GtkDrawCtx* dctx, const XP_Rect* rect )
+{
+    gtkFillRect( dctx, rect, &dctx->grey );
+}
+
 #endif /* PLATFORM_GTK */
 
diff --git a/xwords4/linux/gtkdraw.h b/xwords4/linux/gtkdraw.h
index 452575a3c..0545474dc 100644
--- a/xwords4/linux/gtkdraw.h
+++ b/xwords4/linux/gtkdraw.h
@@ -25,5 +25,6 @@
 DrawCtx* gtkDrawCtxtMake( GtkWidget *widget, GtkGameGlobals* globals );
 
 void draw_gtk_status( GtkDrawCtx* draw, char ch );
+void frame_active_rect( GtkDrawCtx* dctx, const XP_Rect* rect );
 
 #endif