Set initial focus to the check list box.

This is so that when launching the autofilter popup via key stroke,
the user can immediately type-ahead to find a match within the check
list box.

Change-Id: I8a33a52afc6005b4a7428d5f7046eff986da80d2

sc/source/ui/cctrl/checklistmenu.cxx

@@ -1368,6 +1368,7 @@ void ScCheckListMenuWindow::launch(const Rectangle& rRect)
     }
 
     StartPopupMode(aRect, (FLOATWIN_POPUPMODE_DOWN | FLOATWIN_POPUPMODE_GRABFOCUS));
+    cycleFocus(); // Set initial focus to the check list box.
 }
 
 void ScCheckListMenuWindow::close(bool bOK)