QChekBoxList - Unable to Disable a List Item (0.4.22 Version)

I am trying to add QListItems to a QCheckBoxList and I need some of the items to be disabled. However, it doesn't seem to work.
     

      $this->chkBoxList1 = new QCheckBoxList($this);
     
       $lstItem1 = new QListItem(“John”,1);
       $lstItem1->Enabled = false; //I tried the _set('Enabled',false) also
       $lstItem1->Selected = true;
       
       
       $lstItem2 = new QListItem(“Mike”,2);
       $lstItem2->Selected = true;
       $lstItem2->Enabled = true;
       
       
       
       $this->chkBoxList1->AddItem($lstItem1);
       $this->chkBoxList1->AddItem($lstItem2);
     
Any help, really appreciated. I am using the 0.4.22 version which has the Enable function for the QListItem.
Best