Why did my code work before and now suddenly stop?

Just do not use EXPORT FUNCTIONS in future and try to learn a new CODING-STYLE…

$w.onReady(()=>{
    $w('#html2').show();
    $w('#html3').hide();
    $w('#html4').hide();
    $w('#html5').hide();
    $w('#html6').hide();
    $w('#html7').hide();
    $w('#html8').hide();
    //--------------------
    $w('#table1').show();
    $w('#table2').hide();


$w('#switch1').onChange(()=>{
  if($w('#switch1').checked === false){
    $w('#table1').show();
    $w('#table2').hide();
  }
  else if($w('#switch1').checked === true){
    $w('#table1').hide();
    $w('#table2').show();
  }
});

$w('#dropdown1').onChange(()=>{
  if($w("#dropdown1").value === "Ethereum (ETH)"){
    $w('#html2').show();
    $w('#html3').hide();
    $w('#html4').hide();
    $w('#html5').hide();
    $w('#html6').hide();
    $w('#html7').hide();
    $w('#html8').hide();
  }   
  else if($w("#dropdown1").value === "Raven (RVN)"){
    $w('#html2').hide();
    $w('#html3').show();
    $w('#html4').hide();
    $w('#html5').hide();
    $w('#html6').hide();
    $w('#html7').hide();
    $w('#html8').hide();
  }
  else if($w("#dropdown1").value === "Ergo (ERG)"){
    $w('#html2').hide();
    $w('#html3').hide();
    $w('#html4').show();
    $w('#html5').hide();
    $w('#html6').hide();
    $w('#html7').hide();
    $w('#html8').hide();
  }
  
  //better coding .....
  else if($w("#dropdown1").value === "Bitcoin Gold (BTG)"){
    $w('#html2,#html3,#html4,#html6,#html7,#html8').hide('fade');
    $w('#html5').show('fade');
  }
  else if($w("#dropdown1").value === "Eth Classic (ETC)"){
    $w('#html2,#html3,#html4,#html5,#html7,#html8').hide('fade');
    $w('#html6').show('fade');
  }
  else if($w("#dropdown1").value === "Conflux (CFX)"){
    $w('#html2,#html3,#html4,#html5,#html6,#html8').hide('fade');
    $w('#html7').show('fade');
  }
  else if($w("#dropdown1").value === "Cortex (CTXC)"){
    $w('#html2,#html3,#html4,#html5,#html6,#html7').hide('fade');
    $w('#html8').show('fade');
  });
});

Coding this way → any connections to the property-panel needed!

Pay attention → code was edited!