In the parameters of the extension for calculating the cost of delivery in the section Widget settings added the parameter one-page (ajax) order is used.

There are several extensions for creating a one-page checkout. Because of this, errors may occur in the operation of the WT SM CDEK extension, since it is impossible to provide all the ways of implementing third-party developers. Enabling this option can help solve problems with the appearance of a modal window for selecting shipping point and the actual selection of shipping point.