set focus to the window when the mouse is clicked in it explicitly as we don't let the default mouse click handling take place

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60845 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/mousemanager.cpp

@@ -103,6 +103,7 @@ void wxMouseEventsManager::OnLeftDown(wxMouseEvent& event)
     }
 
     m_state = State_Pressed;
+    m_win->SetFocus();
     m_win->CaptureMouse();
     MouseClickBegin(m_item);
 }