Item locking doesn't work as intended

When loading a locked item from string it will not delete the period character properly causing an item index mismatch.

Expected Behavior

The locked item indicator should be deleted when loading the list from a string.

Currently, the character doesn't get deleted.

if (listStr[0] === '.') {
    isLocked = true;
    listStr.substr(1);
}

The substring line needs to be changed to: listStr = listStr.substring(1);