List Editors that support in-place editing can visualize cell values using various controls. For instance, a DateTime value can be displayed using a drop-down date picker. If a Property Editor corresponding to the type of a cell value does not implement the IInplaceEditSupport interface, the cell will be rendered as a simple label. Note that in this case, your Property Editor should be a DXPropertyEditor class inheritor.
The IInplaceEditSupport interface exposes a single IInplaceEditSupport.CreateRepositoryItem method. This method is called when an editable column of cells is created. The method must return a RepositoryItem corresponding to the editor control used by the Property Editor.