This is a change that happened several versions back, but I keep hoping for a change.
I use Opera as my workhorse browser - in short I live there by choice. So it's common for me to find a page online and use "View Source" which I've customized to open the source code in Homesite. That customization is something that Opera offers natively and easily and I've always loved it.
Problem is, these days if Homesite is already open, nothing at all happens when I click "View Source" for an online page -- although a local page opens just fine. When Homesite needs to be opened, then I get a Homesite error message that the file is "not a recognized text document". I can respond to that error message by clicking on "open it anyway".
This means that I must first CLOSE Homesite in order to open the source code of an online page - a time wasting inconvenience. Opera now uses a .tmp file for the source, and I've added that filetype to Homesite's settings - but to no avail. And since Adobe no longer supports Homesite, I can only hope for an Opera change.
Either that or, some kind advice from someone who has resolved this issue.