Diif view autoscrolls back to where it was when trying to manually scroll it

[ricardograca]

Prerequisites

• Have you tried to reproduce the problem in Safe Mode? Yes
• Have you followed all applicable steps in the debugging guide? Most
• Have you checked the FAQs on the message board for common solutions? Yes
• Have you checked that your issue isn't already filed? Yes

Description

Whenever I try to manually scroll the diff view window it auto-scrolls back to where it was before. This only happens if I use the mouse to move the scrollbar. If I use the mouse scroll wheel or Page Up/Down to scroll the view then everything works as expected.

Steps to Reproduce

1. Click on a file with a diff longer than a single page
2. Point to the scrollbar, click and hold
3. Move the mouse up or down so that the view changes accordingly
4. Let go of mouse button

Expected behavior:

The view stays where it was when I let go of the mouse button.

Actual behavior:

The view scrolled itself back to the starting point (step 2 above).

Reproduces how often:

100%

Versions

Atom : 1.23.1
Electron: 1.6.15
Chrome : 56.0.2924.87
Node : 7.4.0

This is on Ubuntu 16.04.3 with all the latest updates.

Additional Information

In the gif above the mouse cursor isn't visible, but the first time the image scrolls down I was doing that, and you can see it going back to the beginning when letting go of the mouse button.

[Arcanemagus]

Should be fixed by #1281 which hasn't been released yet.

Duplicate of #1226 / related to #884.