Empty context menu when tree view doesn't take entire vertical space

[winstliu]

Prerequisites

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  • Reproduced the problem in Safe Mode: http://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
  • Followed all applicable steps in the debugging guide: http://flight-manual.atom.io/hacking-atom/sections/debugging/
  • Checked the FAQs on the message board for common solutions: https://discuss.atom.io/c/faq
  • Checked that your issue isn't already filed: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aatom
  • Checked that there is not already an Atom package that provides the described functionality: https://atom.io/packages

Description

When right-clicking below the bottom-most file in the tree view, the context menu only shows pane commands (ie "Close Pane", "Split Up", etc). #595 seems to have regressed again, probably caused by Docks.

Steps to Reproduce

1. Open Tree View
2. Collapse directories if necessary so that there is blank space at the bottom of the tree view
3. Right-click in that empty space

Expected behavior: To get a relevant context menu that still allows me to add files, paste files, add/remove project folders, etc.

Actual behavior: Only the pane context menu shows up.

Reproduces how often: 100%

Versions

Atom    : 1.18.0-dev-ad86e8488
Electron: 1.6.5
Chrome  : 56.0.2924.87
Node    : 7.4.0

apm  1.17.0
npm  3.10.5
node 6.9.5 x64
python 2.7.12
git 2.12.0.windows.1
visual studio 2015

Windows 10 x64.

/cc @maxbrunsfeld