• VSCode Version: 1.3.0 Insider
• OS Version: OSX

Steps to Reproduce:

1. I have opened multiple tabs in one single group editor
2. Scroll to the last tab in this group
3. Move the cursor into the editor part
4. The tab headers will scroll to left most automatically, which makes it difficult to right click the tab header to open context menu.

It takes me minutes to record above gif as I can't right click the tab header successfully every time.