Set Selected Data for a Check Box List

[font=Roboto, Arial, Helvetica, sans-serif]Hi, I have a form that has a checkbox list (String type). The checkbox list has List Item getting from the output of a flow while selected Item come from data of a field (String List) of an entity. As the list Item getting from the output of a flow, it has no issue to load all items, however as I set input data for Selected Items, it doesnt show as a checked item in the checklist. I tried to set the Data Name of Selected items also as another output of the flow (used to load list item) then it showed correctly. But when I select an item in the checkbox list, the control is always refreshed and clear all selected items to return to original status. I am looking for a simple way to set selected item and to be able to load and save to entity (String List type) in a simple way. It is very simple but I do not know if I did anything wrong. Please give advice.[/font]