diff --git a/src/tests/kits/game/direct_window_test/StarWindow.cpp b/src/tests/kits/game/direct_window_test/StarWindow.cpp
index bfeba8ac7e..81b749d127 100644
--- a/src/tests/kits/game/direct_window_test/StarWindow.cpp
+++ b/src/tests/kits/game/direct_window_test/StarWindow.cpp
@@ -356,7 +356,13 @@ StarWindow::SwitchContext(direct_buffer_info *info)
 	row_bytes = info->bytes_per_row / (info->bits_per_pixel / 8);
 	
 	// update the screen bases (only one of the 3 will be really used).
-	draw_ptr8 = (uint8*)info->bits + (info->bytes_per_row * info->window_bounds.top) + (info->window_bounds.left * (info->bits_per_pixel / 8));
+	draw_ptr8 = (uint8*)info->bits + info->bytes_per_row 
+		* info->window_bounds.top + info->window_bounds.left 
+		* (info->bits_per_pixel / 8);
+		// Note: parenthesis around "info->bits_per_pixel / 8"
+		// are needed to avoid an overflow when info->window_bounds.left
+		// becomes negative.
+		
 	draw_ptr16 = (uint16*)draw_ptr8;
 	draw_ptr32 = (uint32*)draw_ptr8;