diff --git a/src/laybasic/laybasic/layMarker.h b/src/laybasic/laybasic/layMarker.h
index 1b0dd9629..6e57fe28f 100644
--- a/src/laybasic/laybasic/layMarker.h
+++ b/src/laybasic/laybasic/layMarker.h
@@ -245,7 +245,7 @@ class LAYBASIC_PUBLIC MarkerBase
 private:
   tl::Color m_color;
   tl::Color m_frame_color;
-  char m_line_width, m_vertex_size, m_halo;
+  int m_line_width, m_vertex_size, m_halo;
   bool m_text_enabled;
   lay::ViewOp::Shape m_vertex_shape;
   int m_line_style, m_dither_pattern, m_frame_pattern;