[LyX/2.3.x] Enable OK/Apply buttons when resetting to class defaults.

[Juergen Spitzmueller]

commit 8f98423e920d8add7b628debd2266306f438f982
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Wed Nov 1 12:03:54 2017 +0100

    Enable OK/Apply buttons when resetting to class defaults.
    
    (cherry picked from commit b851a349b6f303824f329a5dc854827f66828764)
---
 src/frontends/qt4/GuiDocument.cpp |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/src/frontends/qt4/GuiDocument.cpp 
b/src/frontends/qt4/GuiDocument.cpp
index e80e7ec..385b376 100644
--- a/src/frontends/qt4/GuiDocument.cpp
+++ b/src/frontends/qt4/GuiDocument.cpp
@@ -4149,6 +4149,7 @@ void GuiDocument::useClassDefaults()
        }
        bp_.useClassDefaults();
        paramsToDialog();
+       changed();
 }