Hi Ushinar,
In MultiComboBox, where are you making the selection? Is it on List Item or the Check Box?
If you do the selection on List Item, the drop down will close after first selection -
If you do the selection on check box, it will remain open even though the selection is made -
It is the default behavior of Multi Combobox. If it is behaving the same for check box selection then there might be something wrong. Please let me know if it is closing on selection of check box as well.
Regards,
Sai Vellanki.