Unfortunately I don't see a way to this, Multiselect is only supported in the template mode in Pega platform. I highly doubt even if you turn UI templating OFF across your application, that would make the Multiselect work in a non-template mode. Plus, turning UI templating OFF is not the way FORWARD to be frank. Which is why I think it was intentional to not have a non-templatized version support for this control anymore. The easiest way to get both the Multiselect and the grid to be in the same mode is to switch the grid to use templatization which is what was already offered in the SR.