[LyX/2.2.x] Fixup 1c07c0dc: editable() is unusable in mathed

[Jean-Marc Lasgouttes]

commit 4499680bd9ad415e9bcb19cd09c22dd0d84a1c1d
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Tue Jun 20 09:41:48 2017 +0200

    Fixup 1c07c0dc: editable() is unusable in mathed
    
    This is a relic from IU (Inset Unification): editable() is for text
    insets and isActive() for mathed. This needs to be cleaned up.
    
    Part of bug #10667.
    
    (cherry picked from commit d0acc3e570447b293169b8bdd5ac67aaade189e0)
---
 src/DocIterator.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/DocIterator.cpp b/src/DocIterator.cpp
index a3d81ca..80e67ee 100644
--- a/src/DocIterator.cpp
+++ b/src/DocIterator.cpp
@@ -535,7 +535,7 @@ bool DocIterator::fixIfBroken()
        size_t n = slices_.size();
        for (; i != n; ++i) {
                CursorSlice & cs = slices_[i];
-               if (&cs.inset() != inset || !cs.inset().editable()) {
+               if (&cs.inset() != inset || cs.nargs() == 0) {
                        // the whole slice is wrong, chop off this as well
                        --i;
                        LYXERR(Debug::DEBUG, "fixIfBroken(): inset changed");