Since this morning I have a strange bug.
Usually, I change publishing account like this: In the menu, I select "Project" -> "Publishing", and there I can select the appropriate account.

But since today, this command from the menu has disappeared.
I have only the following choices:
Upload Project
Download Project
Smart Upload
Smart Download
Smart Sync
Upload Project(s)
Upload Folder(s)
Upload File(s)

I checked that I have still two publishing accounts. I even added a third one, but still the problem persists.

I use PhpED 15012 64 bit.

The reason why this may happen is only one -- somehow layout.cfg file returned to version that did not support feature of multiple accounts.
For example if you worked with for example v10, it would "update" this file to its layout -- the layout where no multiple accounts menu implemented.
In order to restore click View -> Restore Default Layout.