Error " Failed to enter text in the edit box, since it is read-only " when editing a WPF application

I don't know if it can help but sometimes, when TC can't set a text I use a little script of my own and doing it in a fully manual way.

Click on the field then using this function :

function super_typing_keyboard(value){
  var i = 0;
  var lt = value.length;
  
  for (;i < lt; i++){
    var chr = aqString.GetChar(value, i);
    var chrK = Win32API.VkKeyScan(aqString.GetChar(value, i));
    var lowByte = chrK & 255;
    var highByte = (chrK >>  8  ) & 255;
    
    // 1 Either SHIFT key is pressed.
    var shift = highByte & 1;
    // 2 Either CTRL key is pressed.
    var ctrl = highByte & 2;
    //4 Either ALT key is pressed.
    var alt = highByte & 4;
    
    if(shift){
      LLPlayer.KeyDown(VK_SHIFT, 50);
      LLPlayer.KeyDown(lowByte, 50);
      LLPlayer.KeyUp(lowByte, 50);
      LLPlayer.KeyUp(VK_SHIFT, 50);
    }else if(alt){
      LLPlayer.KeyDown(VK_MENU, 50);
      LLPlayer.KeyDown(lowByte, 50);
      LLPlayer.KeyUp(lowByte, 50);
      LLPlayer.KeyUp(VK_MENU, 50);
    }else if(ctrl){
      LLPlayer.KeyDown(VK_CONTROL, 50);
      LLPlayer.KeyDown(lowByte, 50);
      LLPlayer.KeyUp(lowByte, 50);
      LLPlayer.KeyUp(VK_CONTROL, 50);
    }else{
      LLPlayer.KeyDown(lowByte, 50);
      LLPlayer.KeyUp(lowByte, 50);
    }
  }
}