Since upgrading to Yosemite from Mountain Lion, the folder disappears from the sidebar. You can put it there, but it won't stay there. I have to go to the actual folder location now. Everything else seems OK so far. Not as easy or convenient as it was in Mountain Lion.
Hello, I just tested it and it works, in some way.....
The reason why it does not behave like an ordinary folder is due to the fact that when you unlock the protected folder, the folder turns into a mount point of a disk image, you can see this if you add the folder when it is locked, it will be listed in the sidebar as a regular folder. But if you unlock it in Espionage, then in the sidebar it will turn into a mounted disk icon.
Now, in my case, when I lock it in Espionage, indeed, this disk icon disappears from the side bar, but when I unlock the folder in Espionage then it reappears. So it is not visible only while the folder is locked.
If you want the folder to be permanently visible in the sidebar, you can put the protected folder into another folder and then put the parent folder into the sidebar.
But I wonder why do you want to keep the folder in the sidebar, it is sufficient to doubleclick the folder in Espionage folder list and it will open in Finder with a new window.
Let me know your comments,
Rgds
Zsolt