Override Ctrl-A accelerator when wxTextCtrl has focus in wxMSW

This key combination is used for selecting all text, while it's also
relatively common to use it as an accelerator for some menu item.

Resolve the conflict in favour of wxTextCtrl, i.e. let it have this key
when it has focus, while still allowing to use it as an accelerator
otherwise.

src/msw/textctrl.cpp

@@ -2048,6 +2048,7 @@ bool wxTextCtrl::MSWShouldPreProcessMessage(WXMSG* msg)
                     {
                         switch ( vkey )
                         {
+                            case 'A':
                             case 'C':
                             case 'V':
                             case 'X':

tests/menu/menu.cpp

@@ -36,6 +36,7 @@ namespace
 enum
 {
     MenuTestCase_Foo = 10000,
+    MenuTestCase_SelectAll,
     MenuTestCase_Bar,
     MenuTestCase_First
 };
@@ -168,6 +169,9 @@ void MenuTestCase::CreateFrame()
 
     fileMenu->Append(MenuTestCase_Foo, "&Foo\tCtrl-F", "Test item to be found");
     m_itemCount++;
+    fileMenu->Append(MenuTestCase_SelectAll, "Select &all\tCtrl-A",
+                     "Accelerator conflicting with wxTextCtrl");
+    m_itemCount++;
 
 
     PopulateMenu(helpMenu, "Helpmenu item ", m_itemCount);
@@ -548,6 +552,11 @@ public:
         return *m_event;
     }
 
+    bool GotEvent() const
+    {
+        return m_gotEvent;
+    }
+
 private:
     void OnMenu(wxCommandEvent& event)
     {
@@ -607,6 +616,24 @@ void MenuTestCase::Events()
                           wxString(src->GetClassInfo()->GetClassName()) );
     CPPUNIT_ASSERT_EQUAL( static_cast<wxObject*>(m_menuWithBar),
                           src );
+
+    // Invoke another accelerator, it should also work.
+    sim.Char('A', wxMOD_CONTROL);
+    wxYield();
+
+    const wxCommandEvent& ev2 = handler.GetEvent();
+    CHECK( ev2.GetId() == MenuTestCase_SelectAll );
+
+    // Now create a text control which uses the same accelerator for itself and
+    // check that when the text control has focus, the accelerator does _not_
+    // work.
+    wxTextCtrl* const text = new wxTextCtrl(m_frame, wxID_ANY, "Testing");
+    text->SetFocus();
+
+    sim.Char('A', wxMOD_CONTROL);
+    wxYield();
+
+    CHECK( !handler.GotEvent() );
 #endif // wxUSE_UIACTIONSIMULATOR
 }