System Information
Win8.1 64bit GTX680

Blender Version
Broken: 2.76.1 2746bbe

Short description of error
When hitting Home key on VSE Preview area, it sometimes doesn't fit well with the full scene dimension.

For example, the LEFT one is by hitting Home key, but the RIGHT one should be expected.
Thanks for checking!

Exact steps for others to reproduce the error
In VSE, hitting Home key when hovering over preview area.