Xcode: split screen on same file. Backspacing causes other side to scroll 1 pixel / 1 line

Number:rdar://30559756 Date Originated:2/16/2017
Status:Open Resolved:
Product:Developer Tools Product Version:Version 8.3 beta 2 (8W120l)
Classification:UI/Usability Reproducible:Sometimes
I was editing the same file in two different window panes (main editor / assistant editor, manual setting, same file).

When I backspace in one pane, the other pane scrolls, sometimes by 1 pixel. As I was volunteering my time to report this problem, it started scrolling by a whole line.

I use black-only code colors because of my chromatic aberration in my eyeglasses.  The SourceServer did not crash.

I see this frequently doing a screenhero share with a junior programmer, but I've been unable to both screen flow it and run screenhero.  It finally misbehaved for me.

gif attached (https://mobile.twitter.com/borkware/status/832300329895153664).  annotated video at [REDACTED]

Steps to Reproduce:
Have main/assistant editor up showing the same file. You might have to go through hoops to get it to actually show the same file rather than the interface.  You're looking at different parts of the file

backspace over some code

Expected Results:
the code backspaces. The other editing pane doesn't move.

Actual Results:
the code backspaces. The other editing pane scrolls, eventually scrolling what I wanted to look at.

Version 8.3 beta 2 (8W120l)
10.12.2 (16C67)

I've seen this for at least the last couple of years during screenshares with another developer.  I rarely use this configuration myself because I try to do most of my coding in other editors with much better split-screen support.


'scroll-me.gif' was successfully uploaded.


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