The latest version, or at least the About says it's up to date:
Version: 26.0.1656.60 - Opera is up to date
Update stream: Stable
System: Windows 8.1 64-bit (WoW64)
Have to admit, I "misspoke", I've been killing the app rather than the individual processes (hadn't looked down the rather long list of processes to see the individual Opera ones); not sure if it will be possible to identify the effected process for the tab that's been hijacked, without a current page suffering from it I can't predict what sort of processing load it might display, if any, that might make it stand out.
Even so, a force close option would definitely be helpful, e.g. if a plugin on a page locks up.