[LyX/master] Properly use top/bottom edit marker for grid inset

[Jean-Marc Lasgouttes]

commit 29fbd062cc58eabfa846e6a18c7f66ef08cae8d3
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Thu Jun 8 16:03:14 2017 +0200

    Properly use top/bottom edit marker for grid inset
    
    This was an oversight when marker() was introduced.
    
    Fixes part of #10688.
---
 src/mathed/InsetMathGrid.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/src/mathed/InsetMathGrid.h b/src/mathed/InsetMathGrid.h
index 886d03a..05bb52a 100644
--- a/src/mathed/InsetMathGrid.h
+++ b/src/mathed/InsetMathGrid.h
@@ -100,6 +100,8 @@ public:
        InsetMathGrid(Buffer * buf, col_type m, row_type n, char valign,
                docstring const & halign);
        ///
+       marker_type marker(BufferView const *) const { return MARKER2; };
+       ///
        void metrics(MetricsInfo & mi, Dimension &) const;
        ///
        void draw(PainterInfo & pi, int x, int y) const;