This pull request causes the "open context menu" unit tests of both Menus (HTML) and Menus (Native Shell) to fail:

```
Error: Expected 301 to be 300.
    at new jasmine.ExpectationResult (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:102:32)
    at null.toBe (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:1194:29)
    at null.<anonymous> (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/spec/Menu-test.js:969:49)
    at jasmine.Block.execute (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:1024:15)
    at jasmine.Queue.next_ (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:1842:31)
    at jasmine.Queue.start (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:1795:8)
    at jasmine.Spec.execute (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:2122:14)
    at jasmine.Queue.next_ (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:1842:31)
    at jasmine.Queue.start (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:1795:8)
    at jasmine.Suite.execute (file:///C:/Users/redmunds/dev/github/brackets-shell/Release/dev/test/thirdparty/jasmine-core/jasmine.js:2267:14)
```

The left position is off by 1, so I suspect it's this change.