only toggle debugs on down, not also on up

Change-Id: I6eb7dfd60ca855a9d4b939f4fd186e7037a1a3b4

vcl/unx/gtk3/gtk3gtkframe.cxx

@@ -388,6 +388,8 @@ void GtkSalFrame::doKeyCallback( guint state,
     vcl::DeletionListener aDel( this );
 
 #if 0
+    if (bDown)
+    {
         // shift-zero forces a re-draw and event is swallowed
         if (keyval == GDK_KEY_0)
         {
@@ -407,6 +409,7 @@ void GtkSalFrame::doKeyCallback( guint state,
             fprintf(stderr, "toggle dump frames to %d\n", dumpframes);
             return;
         }
+    }
 #endif
 
     /*
@@ -453,7 +456,7 @@ void GtkSalFrame::doKeyCallback( guint state,
 
     aEvent.mnCode   |= GetKeyModCode( state );
 
-    if( bDown )
+    if (bDown)
     {
         bool bHandled = CallCallbackExc( SalEvent::KeyInput, &aEvent );
         // #i46889# copy AlternateKeyCode handling from generic plugin