title: OTRS5 - Prevent error dialog on custom new phone ticket screen
body: <p>I am currently customising an <em>OTRS5</em> installation and have created a new link to create a specific type of ticket, which preselects the queue and customer, and fills out the subject automaticlly. I am doing this using the following URL string:</p>
  
  <pre><code>index.pl?Action=AgentTicketPhone;Subaction=StoreNew;Dest=13%7C%7CInternal%3A%3APoC;TypeID=1;Subject=Cylance%20PoC%20Request;CustomerID=999;OTRSAgentInterface=Tyx6YwchDd2S6iDrydUSwpKjuyAcjbqR
  </code></pre>
  
  <p>However, I still want the user to enter a customer user manually but because I am not setting a customer user in the URL it is throwing an error that at least one customer user must be selected. </p>
  
  <p>Does anyone know how to either prevent the error message from happening at all (ideally) or alternatively how I can set a customer user from the URL (as I tried <code>SelectedCustomerUser=*</code> and <code>PreSelectedCustomerUser=*)</code> but neither of them did anything.</p>
  
  <p>Any help with this issue would be much appreciated :)</p>