collapsible editable grid with selection check boxes

Please take a look at the code below. I have made minor changes and also update local!selectedvalues using the variable where you want to save the values. Please make sure you save only the primary keys of the child data to avoid any duplicates and issues in the code.

a!localVariables(
  local!prs: {
    a!map(id: 1, summary: "PR1"),
    a!map(id: 2, summary: "PR2"),
    a!map(id: 3, summary: "PR3"),
    
  },
  local!items: {
    a!map(
      id: 1,
      summary: "item 1",
      qty: "2",
      unitPrice: "100",
      purchaseRequestid: 1
    ),
    a!map(
      id: 2,
      summary: "item 4",
      qty: "3",
      unitPrice: "200",
      purchaseRequestid: 1
    ),
    a!map(
      id: 3,
      summary: "item 7",
      qty: "2",
      unitPrice: "250",
      purchaseRequestid: 3
    ),
    a!map(
      id: 4,
      summary: "item 11",
      qty: "2",
      unitPrice: "30",
      purchaseRequestid: 2
    ),
    a!map(
      id: 5,
      summary: "item 31",
      qty: "6",
      unitPrice: "220",
      purchaseRequestid: 2
    )
  },
  local!selectedValues,
  a!gridLayout(
    headerCells: {
      a!gridLayoutHeaderCell(label: ""),
      a!gridLayoutHeaderCell(label: "Summary"),
      a!gridLayoutHeaderCell(label: "Qty", align: "RIGHT"),
      a!gridLayoutHeaderCell(label: "Unit Price", align: "RIGHT"),
      a!gridLayoutHeaderCell(label: "Total Price", align: "RIGHT")
    },
    columnConfigs: {
      a!gridLayoutColumnConfig(width: "ICON"),
      a!gridLayoutColumnConfig(width: "DISTRIBUTE", weight: 4),
      a!gridLayoutColumnConfig(width: "DISTRIBUTE"),
      a!gridLayoutColumnConfig(width: "DISTRIBUTE", weight: 2),
      a!gridLayoutColumnConfig(width: "DISTRIBUTE", weight: 2)
    },
    rowHeader: 1,
    rows: a!forEach(
      items: local!prs,
      expression: a!localVariables(
        local!expanded: false,
        local!itemsForPr: index(
          local!items,
          /* Must cast to integer because a!queryEntity() returns a dictionary */
          wherecontains(
            tointeger(fv!item.id),
            local!items.purchaseRequestid
          ),
          {}
        ),
        local!totalPrice: sum(
          a!forEach(
            items: local!itemsForPr,
            expression: tointeger(fv!item.qty) * todecimal(fv!item.unitPrice)
          )
        ),
        {
          a!gridRowLayout(
            contents: {
              a!textField(value: null, readOnly: true),
              a!richTextDisplayField(
                label: "Summary " & fv!index,
                value: {
                  if(
                    length(local!itemsForPr) = 0,
                    fv!item.summary,
                    a!richTextItem(
                      text: if(local!expanded, "-", "+") & " " & fv!item.summary,
                      link: a!dynamicLink(
                        value: not(local!expanded),
                        saveInto: local!expanded
                      )
                    )
                  )
                }
              ),
              a!textField(label: "Qty " & fv!index, readOnly: true),
              a!textField(
                label: "Unit Price " & fv!index,
                readOnly: true
              ),
              a!textField(
                label: "Total Price " & fv!index,
                value: a!currency(isoCode: "USD", value: local!totalPrice),
                readOnly: true,
                align: "RIGHT"
              )
            }
          ),
          if(
            local!expanded,
            a!forEach(
              items: local!itemsForPr,
              expression: a!gridRowLayout(
                contents: {
                  a!richTextDisplayField(
                    value: a!richTextIcon(
                      icon: if(
                        contains(
                          tointeger(local!selectedValues),
                          fv!item.id
                        ),
                        "check-square",
                        "square-o"
                      ),
                      link: a!dynamicLink(
                        value: fv!item.id,
                        saveInto: if(
                          contains(
                            tointeger(local!selectedValues),
                            fv!item.id
                          ),
                          a!save(
                            local!selectedValues,
                            remove(
                              local!selectedValues,
                              wherecontains(fv!item.id,local!selectedValues)
                            )
                          ),
                          a!save(
                            local!selectedValues,
                            append(local!selectedValues, fv!item.id)
                          )
                        )
                      ),
                      linkStyle: "STANDALONE"
                    )
                  ),
                  a!richTextDisplayField(
                    label: "Item Summary " & fv!index,
                    value: a!richTextBulletedList(items: fv!item.summary)
                  ),
                  a!integerField(
                    label: "Item Qty " & fv!index,
                    value: fv!item.qty,
                    readOnly: true,
                    align: "RIGHT"
                  ),
                  a!textField(
                    label: "Item Unit Price " & fv!index,
                    value: a!currency(isoCode: "USD", value: fv!item.unitPrice),
                    readOnly: true,
                    align: "RIGHT"
                  ),
                  a!textField(
                    label: "Item Total Price " & fv!index,
                    value: a!currency(
                      isoCode: "USD",
                      value: tointeger(fv!item.qty) * todecimal(fv!item.unitPrice)
                    ),
                    readOnly: true,
                    align: "RIGHT"
                  )
                }
              )
            ),
            {}
          )
        }
      )
    )
  )
)