[LyX/master] Fix display of empty box in nested macros

[Jean-Marc Lasgouttes]

commit d221d1734a619dd1046b0588793683110c64f542
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Mon Jan 9 18:23:17 2017 +0100

    Fix display of empty box in nested macros
    
    The rewrite of nesting handling at 0f15dcc6 was incomplete: the
    macro nesting has to be reset to 0 when inside a macro argument at
    level 1.
---
 src/mathed/MathMacro.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/mathed/MathMacro.cpp b/src/mathed/MathMacro.cpp
index 1311bc9..7670f48 100644
--- a/src/mathed/MathMacro.cpp
+++ b/src/mathed/MathMacro.cpp
@@ -82,7 +82,8 @@ public:
                // macro arguments are in macros
                LATTEST(mathMacro_->nesting() > 0);
                /// The macro nesting can change display of insets. Change it 
locally.
-               Changer chg = make_change(mi.base.macro_nesting, 
mathMacro_->nesting());
+               Changer chg = make_change(mi.base.macro_nesting,
+                                         mathMacro_->nesting() == 1 ? 0 : 
mathMacro_->nesting());
 
                MathRow::Element e_beg(MathRow::BEG_ARG);
                e_beg.macro = mathMacro_;