@JohnSl You can't currently filter the lightning component in the same way as a button. You could use a button in lightning if this is required. What do you need to be able to do with the contact you are trying to auto select?

@leighburke thanks for your reply I thought that might be the case.

We have a docgen package to send a letter as an attachment using salesforce email. Some of our users are selecting the wrong contact as we have thousands of contacts some with a same or very near same name. If they dont duble check against the case contact before sending then the ltter could be sent to the wrong person. So i wanted to filter so when docgen is launched from the case object it can only list that case contact.

@JohnSl Rather than having the user select the contact, you could instead use the tag from your relationship in the email delivery. This would pull the contact related to the record rather than the selection, you will need to select the internal email option as this removes the requirement for selecting a contact.

Is it still the case that you can't filter the lightning component in the same way as a button?