One option may be to compromise and use a list box display option instead on the state form, but it is not top of mind if it shows the whole list. An extreme option could be to create an Advanced Report (https://knowledgebase.serena.com/InfoCenter/index?page=content&id=S141342&actp=search&viewlocale=en_US&searchid=1643911836745) to gain access to the list of values in TS_SELECTIONS and then use tricks on top of that to visualize the data.

I used an embedded JavasciptWidget and <DIV> tag along with a separate ASP page on the webapp server and got the job done.  

<script>

    var xmlHttp = new XMLHttpRequest();

    var theURL = "https://..../ToDoList.asp?DoneTasks={ToDoTaskList}&TaskType={ToDoTaskType[ID]}"

    xmlHttp.open( "GET", theURL, false ); // false for synchronous request

    xmlHttp.send();

    document.getElementById("ToDoListDIV").innerHTML=xmlHttp.responseText;

</script>

<DIV id="ToDoListDIV"></DIV>

The asp page checks the boxes that are done from the ToDoTaskList field and filters the entire list using ToDoTaskType[ID] to only display the task checkboxes that are needed. 

ASP Script

<%
tasktype=Request.QueryString("TaskType")
DoneTasks=Request.QueryString("DoneTasks")

%>
<%
Dim Recordset1
Dim Recordset1_cmd
Dim Recordset1_numRows

Set Recordset1_cmd = Server.CreateObject ("ADODB.Command")
Recordset1_cmd.ActiveConnection = MM_ABShelpProd_STRING
Recordset1_cmd.CommandText = "SELECT * FROM TSM_SRC_ITSBUCUSTOMERTASKS WHERE TS_ID<>0 AND TS_TODOTASKTYPE='"&TaskType&"'"
Recordset1_cmd.Prepared = true

Set Recordset1 = Recordset1_cmd.Execute
Recordset1_numRows = 0
%>
<%
Dim Repeat1__numRows
Dim Repeat1__index

Repeat1__numRows = -1
Repeat1__index = 0
Recordset1_numRows = Recordset1_numRows + Repeat1__numRows
%>

<%
While ((Repeat1__numRows <> 0) AND (NOT Recordset1.EOF))
%>
<input name="ToDoListoption" type="checkbox" value="1" <%if InStr(DoneTasks,Recordset1("TS_TITLE"))>0 then%> checked="checked"<%end if%> disabled="disabled" /> <%=(Recordset1("TS_TITLE"))%><br />

<%
Repeat1__index=Repeat1__index+1
Repeat1__numRows=Repeat1__numRows-1
Recordset1.MoveNext()
Wend
%>

<%
Recordset1.Close()
Set Recordset1 = Nothing
%>