Open Radar

 
Summary:
The macOS "U.S International - PC" keyboard is very convenient for people who want an U.S. keyboard configuration but also want to type characters like ä, ü, ï, ñ, é, å since it has a special behavior where "+a becomes ä and '+e becomes é.

When the system keyboard setting is "U.S International - PC", using Xcode 9 and typing a single straight double quote (") and then pressing spacebar or the right arrow key (used to write a plain straight quotation mark the isn't combined with the character after it) instead inserts 3 straight quotation marks and breaks syntax highlighting for everything that comes after in that file.

This used to work in Xcode 8.

After removing the 3 quotation marks, the lines below still has no syntax highlighting and needs to be modifier to get it back.

Steps to Reproduce:
1. Open the Xcode 9 source editor in either a project or a playground
2. Set the system keyboard Input Source to "U.S International - PC"
3. Write some code that gets syntax highlighting 
4. On any line - that isn't the last of that file - type " and press spacebar

(See attached GIF)

Expected Results:
A single " is added to the source file.

Observed Results:
When spacebar is pressed a total of 3 " is added to the source file and syntax highlighting disappears for every line after the edited line.

Version:
Xcode Version 9.0 beta (9M136h)
macOS Version 10.12.5 (16F73)

Notes:
Xcode 8 and other applications like TextEdit and Notes has the expected behavior.

Configuration: