No unsubscribe after 2 last updates


After the last two updates (via git) the web frontend has problems unsubscribing from feeds.
“Unsubscribe from feed” has no effect in frontend and backend (“Unsubscribe from feed…” -> Button “Ok”)
The official Android App does it.

tt-rss version (including git commit id):
v17.4 (c9040c5)

Platform (i.e. Linux distro, PHP, PostgreSQL, etc) versions:
Linux Ubuntu Server 14.04


As with my other thread i tracked it down to some browser problems. Firefox seems to be the problem. Chrome does it.
Web-Console and server side error log show nothing.