How to revert Open Quickly back to dark theme on Xcode 9.3?

Question

I've just updated Xcode to 9.3 and I've noticed that "Open Quickly" ( cmdshiftO) interface have reverted to white theme (instead of black on previous versions, which obeyed my Mac's color theme, which is dark):

My Mac's theme is the dark theme and, for example, Spotlight Search obeys it:

Xcode's Open Quickly was also dark like Spotlight Search too, until I updated. Why would have it turned to light theme and how do I make it obey the system theme again?

Answer 1

As far as I know there's no easy way to get back the dark theme. It's possible, but it involves unsigning Xcode and byte patching the DVTKit binary that's in the Xcode bundle. I wrote a blog post about this a few days ago. In summary, to get back the dark Open Quickly theme in Xcode 9.3*, perform the following steps (at your own risk):

1. Download Hex Fiend
2. Open Xcode.app/Contents/SharedFrameworks/DVTKit.framework/Versions/A/DVTKit in Hex Fiend.
3. Navigate to adress 0x00000000000163cd using Edit > Jump to Offset.
4. Replace the byte right after the insertion point that says 31 with 09.
5. Save.
6. Download unsign and follow the installation instructions.
7. Unsign the Xcode binary using $ unsign Xcode.app/Contents/MacOS/Xcode. This will produce a new binary.
8. Replace the signed Xcode binary with the unsigned binary using $ mv Xcode.app/Contents/MacOS/Xcode.unsigned Xcode.app/Contents/MacOS/Xcode
9. Launch Xcode and revel in the return of the dark Open Quickly theme.

* Only tested on Xcode 9.3 (9E145) downloaded from the Apple Developer Portal

With that said, it's probably not worth the effort :-) Since the dark theme is still there (but disabled) I would expect it to return in one of the next Xcode releases. It might even be there in the Xcode 9.4 beta (I haven't tried it yet).