菜单明明可以通过上移进行显示，但它竟然缩小了！

[yuzexun]

Issue Type: Bug

打开一个.cpp文件，我在编辑区上面点击右键弹出菜单，若是在屏幕中间点击，可以完整显示16个菜单选项，但我鼠标再往下移，然后右键弹出菜单，就会发现，越往下移，菜单项就会显示的越来越少，一直会跟随鼠标点击的位置，但菜单项显示不全。 这个显示得下应该自动调整吧，这样的菜单太难使用了。

VS Code version: Code 1.30.1 (dea8705087adb1b5e5ae1d9123278e178656186a, 2018-12-18T18:05:00.654Z) OS version: Darwin x64 18.2.0

System Info

|Item|Value| |---|---| |CPUs|Intel(R) Core(TM) i7-4980HQ CPU @ 2.80GHz (8 x 2800)| |GPU Status|2d_canvas: enabled
checker_imaging: disabled_off
flash_3d: enabled
flash_stage3d: enabled
flash_stage3d_baseline: enabled
gpu_compositing: enabled
multiple_raster_threads: enabled_on
native_gpu_memory_buffers: enabled
rasterization: enabled
video_decode: enabled
video_encode: enabled
webgl: enabled
webgl2: enabled| |Load (avg)|4, 3, 3| |Memory (System)|16.00GB (0.21GB free)| |Process Argv|-psn_0_167977| |Screen Reader|no| |VM|0%|

Extensions (33)

Extension|Author (truncated)|Version ---|---|--- unity-snippets|Ycl|0.1.2 android-dev-ext|ade|0.6.2 code-gnu-global|aus|0.2.2 npm-intellisense|chr|1.3.0 path-intellisense|chr|1.4.2 xml|Dot|2.4.0 eppz-code|epp|1.2.41 csharpextensions|jch|1.3.0 webpack|jer|2.1.0 svn-scm|joh|1.47.0 docomment|k--|0.1.2 luaide|kan|0.7.5 node-module-intellisense|lei|1.5.0 cpp-symbols|mir|0.0.1 vscode-clang|mit|0.2.3 vscode-language-pack-zh-hans|MS-|1.30.2 cpptools|ms-|0.20.1 csharp|ms-|1.17.1 mono-debug|ms-|0.15.8 debugger-for-chrome|msj|4.11.1 gradle-language|nac|0.2.3 java|red|0.36.0 LiveServer|rit|5.3.1 shader|sle|1.1.4 vscode-hexdump|sle|1.7.2 factorio-lua-api-autocomplete|svi|0.6.0 unity-tools|Tob|1.0.5 unity-debug|Uni|2.6.6 vscode-java-debug|vsc|0.16.0 vscode-java-dependency|vsc|0.3.0 vscode-java-pack|vsc|0.5.0 vscode-java-test|vsc|0.13.0 vscode-maven|vsc|0.12.1

[egamma]

Please report issues in english.