The 16 words below may be partitioned into 4 groups of 4 thematically connected words.
What are those connections and groups?
The puzzle format is from BBC Television's quiz show Only Connect.
This wall is probably more suitable for Puzzling.SE than the show (although the shows are tough).
Currently correctly identified groups and who found them:
Shift, Option, Control, Alternate identified as (1) by M Oehm
Black, Red, Lane, Stock identified as (2) by ArgumentBargument
If you look at this information (including removal of the possibility of other, incorrectly identified, groups), please do upvote their finds! (Infact, do if you look at their spoiler text also).
Brent Hackers' Bounty Hint
One of the remaining groups
...is connected by a property of something often seen here and there on Puzzling, sometimes in the puzzles, sometimes in comments, and occasionally even in chat; have a look around and see what is the same - I really do hope it does not irk/vex.