[LyX/master] Fix undo after breaking a nested paragraph

[Jean-Marc Lasgouttes]

commit 57feb0fed0c078903900aaea069c49207c8cb9ac
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Fri Nov 23 16:53:53 2018 +0100

    Fix undo after breaking a nested paragraph
    
    We have to take into account that Buffer::updateBuffer can modify the 
document.
    
    Fix bug #11292.
---
 src/frontends/qt4/GuiApplication.cpp |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/frontends/qt4/GuiApplication.cpp 
b/src/frontends/qt4/GuiApplication.cpp
index c476109..b9ba830 100644
--- a/src/frontends/qt4/GuiApplication.cpp
+++ b/src/frontends/qt4/GuiApplication.cpp
@@ -1412,11 +1412,13 @@ DispatchResult const & 
GuiApplication::dispatch(FuncRequest const & cmd)
                // This handles undo groups automagically
                UndoGroupHelper ugh(buffer);
                dispatch(cmd, dr);
+               // redraw the screen at the end (first of the two drawing 
steps).
+               // This is done unless explicitly requested otherwise.
+               // This code is kept inside the undo group because updateBuffer
+               // can create undo actions (see #11292)
+               updateCurrentView(cmd, dr);
        }
 
-       // redraw the screen at the end (first of the two drawing steps).
-       // This is done unless explicitly requested otherwise
-       updateCurrentView(cmd, dr);
        d->dispatch_result_ = dr;
        return d->dispatch_result_;
 }