partialMatchTimeout not used with a key combo that is both a prefix and bound to a command

[dimfeld]

Atom 1.7.2 on OSX 10.11.4

When a particular key combination is bound to a command and is also a prefix for other commands, the partialMatchTimeout doesn't appear to work properly.

Easiest steps to reproduce:

1. Install git-plus package
2. Look at the package settings and note the default keybindings have commands mapped to cmd-shift-a and cmd-shift-a s (and others)
3. Open a file inside a git repo.
4. Open key binding resolver
5. Press cmd-shift-a
6. Wait 1 second, and note that it's still waiting. (It appears to wait indefinitely)
7. Press up arrow or anything else that cancels the wait. Only then does the git-plus:add command run.

To ensure this wasn't directly related to the git-plus package, I've also reproduced this in safe mode by binding a command such as core:copy to cmd-k, which has a number of 2-stroke bindings already set up.

See akonwi/git-plus#415 and akonwi/git-plus#419 for some related discussion. Some people there say this behavior appeared in the 1.5 branch, maybe between 1.5.3 and 1.5.4.

[banacorn]

+1. This is really annoying