[LyX/master] Add getStatus check that >1 tab for switching

[Scott Kostyshak]

commit e26ac5c5506a7e37ac24e696aaa3b7b1e721dbcb
Author: Scott Kostyshak <skost...@lyx.org>
Date:   Tue Apr 7 22:55:20 2015 -0400

    Add getStatus check that >1 tab for switching
    
    buffer-next and buffer-previous are now only enabled
    if there is more than one tab. Note that it does not
    matter whether we are at the first or last tab because
    we cycle.

diff --git a/src/frontends/qt4/GuiView.cpp b/src/frontends/qt4/GuiView.cpp
index 6ac7471..65fe919 100644
--- a/src/frontends/qt4/GuiView.cpp
+++ b/src/frontends/qt4/GuiView.cpp
@@ -1922,9 +1922,12 @@ bool GuiView::getStatus(FuncRequest const & cmd, 
FuncStatus & flag)
                break;
 
        case LFUN_BUFFER_NEXT:
-       case LFUN_BUFFER_PREVIOUS:
-               // FIXME: should we check is there is an previous or next 
buffer?
+       case LFUN_BUFFER_PREVIOUS: {
+               // because we cycle, it doesn't matter whether on first or last
+               if (d.currentTabWorkArea()->count() <= 1)
+                       enable = false;
                break;
+       }
        case LFUN_BUFFER_SWITCH:
                // toggle on the current buffer, but do not toggle off
                // the other ones (is that a good idea?)