For consistency with the generic version and because it makes more sense than
blocking in the dialog destructor (which is the only other alternative for the
dialogs without wxPD_AUTO_HIDE to work), we should block in Update() when the
maximal value is reached for dialogs without wxPD_AUTO_HIDE style until the
dialog is dismissed.
Document this behaviour even more clearly.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65507 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775