Make undo action no-ops when the buffer is read-only

[lyx.git] / src / mathed / InsetMathSubstack.cpp

diff --git a/src/mathed/InsetMathSubstack.cpp b/src/mathed/InsetMathSubstack.cpp
index ed90338fb6934e3ce97257ddd554967be8da2d03..11678b559d91226093474bbe052d1477fed7ad90 100644 (file)
--- a/src/mathed/InsetMathSubstack.cpp
+++ b/src/mathed/InsetMathSubstack.cpp
@@ -100,6 +100,8 @@ void InsetMathSubstack::infoize(odocstream & os) const
 void InsetMathSubstack::write(TeXMathStream & os) const
 {
        MathEnsurer ensurer(os);
+       if (os.fragile())
+               os << "\\protect";
        os << "\\substack{";
        bool open = os.startOuterRow();
        InsetMathGrid::write(os);