[LyX/2.0.x] Return true to indicate we might have invalidated the cursor

[Vincent van Ravesteijn]

commit 1f13491f06dbcaf2d942f84133441872787bc436
Author: Vincent van Ravesteijn <v...@lyx.org>
Date:   Fri Feb 7 17:14:36 2014 +0100

    Return true to indicate we might have invalidated the cursor
    
    If we don't do so, Cursor::notifyCursorLeavesOrEnters might continue with
    an invalidated cursor.
    
    Fixes-bug: #8329

diff --git a/src/mathed/MathMacroTemplate.cpp b/src/mathed/MathMacroTemplate.cpp
index 2989e2b..9f05fe7 100644
--- a/src/mathed/MathMacroTemplate.cpp
+++ b/src/mathed/MathMacroTemplate.cpp
@@ -624,10 +624,13 @@ void MathMacroTemplate::edit(Cursor & cur, bool front, 
EntryDirection entry_from
 
 bool MathMacroTemplate::notifyCursorLeaves(Cursor const & old, Cursor & cur)
 {
+       unsigned int const nargs_before = nargs();
        commitEditChanges(cur, old);
        updateLook();
        cur.screenUpdateFlags(Update::Force);
-       return InsetMathNest::notifyCursorLeaves(old, cur);
+       // If we have removed a cell, we might have invalidated the cursor
+       return InsetMathNest::notifyCursorLeaves(old, cur)
+               || nargs() < nargs_before;
 }