Hide combobox popup when it is hidden itself in wxMSW.

It was possible to hide the main part of a combobox control but keep its popup
shown and this notably happened in wxGrid when TAB was pressed while a
wxChoice cell editor was dropped down.

Avoid this Cheshire combobox syndrome by explicitly dismissing the popup when
a combobox is hidden.

Closes #3113.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71104 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/choice.h

@@ -66,6 +66,8 @@ public:
                 const wxValidator& validator = wxDefaultValidator,
                 const wxString& name = wxChoiceNameStr);
 
+    virtual bool Show(bool show = true);
+
     virtual void SetLabel(const wxString& label);
 
     virtual unsigned int GetCount() const;

src/msw/choice.cpp

@@ -646,6 +646,19 @@ void wxChoice::MSWDoPopupOrDismiss(bool show)
     ::SendMessage(GetHwnd(), CB_SHOWDROPDOWN, show, 0);
 }
 
+bool wxChoice::Show(bool show)
+{
+    if ( !wxChoiceBase::Show(show) )
+        return false;
+
+    // When hiding the combobox, we also need to hide its popup part as it
+    // doesn't happen automatically.
+    if ( !show && ::SendMessage(GetHwnd(), CB_GETDROPPEDSTATE, 0, 0) )
+        MSWDoPopupOrDismiss(false);
+
+    return true;
+}
+
 // ----------------------------------------------------------------------------
 // MSW message handlers
 // ----------------------------------------------------------------------------