[LyX/master] Fix Cursor::inCoordCache: the root inset is never in the cache

[Jean-Marc Lasgouttes]

commit e8e97d67d902cbea41aa6425316ece5c2c3b7dc4
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Fri Mar 11 15:13:05 2016 +0100

    Fix Cursor::inCoordCache: the root inset is never in the cache
    
    Fixes bug #10007.

diff --git a/src/Cursor.cpp b/src/Cursor.cpp
index e9bdf89..8d94ddf 100644
--- a/src/Cursor.cpp
+++ b/src/Cursor.cpp
@@ -550,8 +550,11 @@ int Cursor::currentMode()
 
 bool Cursor::inCoordCache() const
 {
+       // the root inset is not in cache, but we do not need it.
+       if (depth() == 1)
+               return true;
        CoordCache::Insets const & icache = bv_->coordCache().getInsets();
-       for (size_t i = 0 ; i < depth() ; ++i)
+       for (size_t i = 1 ; i < depth() ; ++i)
                if (!icache.has(&(*this)[i].inset()))
                        return false;
        return true;