virtualedit's 'all' doesn't combine with 'block'

[mkoskar]

I have set virtualedit=block and [ov ]ov cov mappings doesn't do anything.

I would expect to all take effect and I suppose that was the idea behind current implementation that appends all to whatever the value of virtualedit is. Judging from :help virtualedit and some testing if all is to work it has to be a single value.