Hi,
Thanks for using Syncfusion products.
I am able to reproduce the issue that you have mentioned, this is because of, you have given different field names for DataTextField and DataValueField.
DataTextField - Field in the data source which provides the item Text.
DataValueField - Field in the data source which provides the item Value.
If you wants to have both to be same you have bind these properties with same fields. Please refer the below code snippet which illustrates this:
this.MultiSelectionDropDown1.DataSource = dt;
this.MultiSelectionDropDown1.DataTextField = "Value";
this.MultiSelectionDropDown1.DataValueField = "Value";
this.MultiSelectionDropDown1.DataBind();
Please refer the sample from the below link which illustrates this:
http://websamples.syncfusion.com/samples/Tools.Web/6.1.0.34/I40893/main.htmPlease let me know if this helps you out.
Regards,
Raji