[LyX/master] Fix assertion in editing math (bug #8946)

[Juergen Spitzmueller]

commit b13f5dee53115f6619c1f0fd5bcfb7ebf031feae
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Thu Feb 6 11:08:33 2014 +0100

    Fix assertion in editing math (bug #8946)

diff --git a/src/frontends/qt4/Menus.cpp b/src/frontends/qt4/Menus.cpp
index bfb0d70..6816986 100644
--- a/src/frontends/qt4/Menus.cpp
+++ b/src/frontends/qt4/Menus.cpp
@@ -1666,13 +1666,13 @@ void 
MenuDefinition::expandEnvironmentSeparators(BufferView const * bv)
        if (!bv)
                return;
 
-       Paragraph const par = bv->cursor().paragraph();
+       pit_type pit = bv->cursor().pit();
+       Paragraph const & par = bv->buffer().text().getPar(pit);
        docstring const curlayout = par.layout().name();
        docstring outerlayout;
        depth_type current_depth = par.params().depth();
        // check if we have an environment in our nesting hierarchy
-       pit_type pit = bv->cursor().pit();
-       Paragraph cpar = bv->buffer().text().getPar(pit);
+       Paragraph cpar = par;
        while (true) {
                if (pit == 0 || cpar.params().depth() == 0)
                        break;