VS Code Ligature Issue: Fonts Render Incorrectly

Hey guys,

I've run into a bit of a visual glitch in VS Code and wanted to share it with you all. It seems like there's an issue with how fonts with ligatures are rendered, and it's making my code look a little wonky. Let's dive into the details so you can see what I'm talking about and hopefully, we can get this sorted out!

The Problem: Ligatures Gone Wrong

The Bug: All fonts with ligatures enabled are rendered incorrectly in VS Code.

To illustrate the issue, I've set my editor to use the Monaspace font with texture healing enabled. Here’s the configuration I’m using in my settings.json:

"editor.fontFamily": "'Monaspace Neon', monospace",
"editor.fontLigatures": "'calt', 'liga'"

Now, let's take a look at how it renders in VS Code compared to how it should look.

Here’s how it’s rendered incorrectly in VS Code:

And here’s the expected rendering, which I see in another editor:

As you can see, the ligatures aren't quite rendering as they should in VS Code, which can make the code a bit harder to read.

Digging into the Details

To give you a full picture, here’s my VS Code and system information:

• VS Code version: Code 1.102.3 (Universal) (488a1f239235055e34e673291fb8d8c810886f81, 2025-07-29T03:00:23.339Z)
• OS version: Darwin arm64 24.6.0
• Modes: (More on this below)

System Info

Let's break down the system info to give you the nitty-gritty details:

So, I’m running VS Code on an Apple M4 chip with 16GB of RAM, and the GPU seems to be well-equipped with various features enabled. The system load is pretty low, so it doesn’t seem like performance is the issue here.

A/B Experiments

Here’s a list of A/B experiments that are currently active in my VS Code setup:

vsliv368:30146709
pythonvspyt551:31249599
binariesv615:30325510
h48ei257:31000450
nativeloc1:31344060
dwcopilot:31170013
6074i472:31201624
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythoneinst12:31285622
c7cif404:31314491
996jf627:31283433
pythonrdcb7:31342333
usemplatestapi:31297334
0aa6g176:31307128
747dc170:31275177
aj953862:31281341
generatesymbolt:31295002
convertfstringf:31295003
pylancequickfixf:31358881
9d2cg352:31346308
convertlamdaf:31358879
usemarketplace:31343026
nesew2to5:31336538
agentclaude:31350858
replacestringexc:31350595
nes-set-on:31351930
testaa123:31335226
6abeh943:31336334
envsdeactivate2:31353495
yijiwantestdri0626-c:31336931
0927b901:31350571
ji9b5146:31348712
45650338:31358607
0cj2b977:31352657

It's a long list, but it gives you an idea of the experiments that might be influencing the behavior of VS Code on my system. It's possible that one of these experiments is inadvertently causing the ligature rendering issue.

Why Ligatures Matter

Okay, so why are ligatures important anyway? Ligatures are special characters that combine two or more letters into a single glyph. They're designed to improve readability and aesthetics in code by making certain character combinations look more visually appealing and less cramped. For example, the characters != might be combined into a single ≠-like glyph, or => might become a single arrow-like character. When ligatures don't render correctly, it can make the code harder to scan and understand at a glance.

Fonts and Their Features

Fonts with ligatures, like Monaspace Neon, are created with specific features that enable these character combinations. These features are typically controlled by OpenType font features such as calt (contextual alternatives) and liga (standard ligatures). In my settings.json, I’ve explicitly enabled these features:

"editor.fontLigatures": "'calt', 'liga'"

This tells VS Code to use these features when rendering the font. However, if something goes wrong in the rendering pipeline, the ligatures might not display as intended.

Potential Causes and Troubleshooting

So, what could be causing this issue? Here are a few possibilities:

1. Rendering Engine Glitches: VS Code uses a rendering engine to display text, and there might be a bug in this engine that's affecting ligature rendering. This could be specific to certain fonts or font features.
2. Font Feature Support: It's possible that VS Code's rendering engine doesn't fully support all OpenType features, or that there's a conflict with how these features are implemented in certain fonts.
3. Extension Conflicts: Sometimes, extensions can interfere with VS Code's core functionality. It's worth checking if any installed extensions might be affecting font rendering.
4. GPU Issues: Although my GPU seems capable, there could be specific issues with how VS Code is utilizing it for text rendering. Driver problems or compatibility issues could potentially cause rendering glitches.

To troubleshoot this, here are some steps I might take:

• Disable Extensions: Try disabling extensions one by one to see if any of them are causing the problem.
• Test Different Fonts: Try other fonts with ligatures to see if the issue is specific to Monaspace Neon.
• Update VS Code: Make sure I’m running the latest version of VS Code, as updates often include bug fixes.
• Check GPU Drivers: Ensure my GPU drivers are up to date.
• Experiment with Settings: Try tweaking VS Code's rendering-related settings to see if anything changes the behavior.

Wrapping Up

So, there you have it – a detailed look at the ligature rendering issue I’m experiencing in VS Code. I hope this write-up helps the VS Code team identify and fix the problem. In the meantime, I’ll keep experimenting with different settings and troubleshooting steps to see if I can find a workaround. If you guys have any ideas or have experienced something similar, please let me know in the comments! Let's get those ligatures looking sharp again!