Cursor rendering issue in Python Interpreter started with latest VS code version, 1.86.0

[julianghadially]

Type: Bug

Behaviour

Expected vs. Actual

I'm experiencing a very disruptive cursor rendering issue in python interpreter, when I updated to the latest vs code 1.86.0. The cursor in the python interpreter gets stuck on code lines that span multiple lines: When tracking to the left, the rendering gets stuck and edits at a different location than displayed. Vs Expected: you should be able to scroll to the left and have the cursor not get stuck.

I reverted VS Code and python extension to older versions, and the issue was still present.

System information: VS code version 1.86.0 and 1.85.2 (tried fixing across multiple versions)
Python version: 2024.0.0 and 2025.25.10292213.vsix

Steps to reproduce:

1. Step 1: Update to VS code 1.86.0
2. Step 2: paste a multi-line command into the terminal

3. Step 3: use the left arrow to navigate left until you reach the prior line. The rendered cursor stopped before reaching the prior lines, despite how many times I press left. I pressed the left arrow key ~10-11 times.

4. Step 4: Try pressing backspace, and the actual cursor was editing a place 10-11 characters to the left of where the cursor was stuck. (i.e., the i from simple was deleted instead of the t from prompt:

After this error, if you press the down arrow, the cursor rendering is way off in random places, and it gets really wacky (e.g., cursors in the middle of the screen, etc.

The problem does not occur when I start python from the terminal.

Ultimately, I need a way to send multi-line blocks to the terminal line-by-line (e.g., using shift-enter). This is a critical efficiency need that dictates which ide I use. There weren't any problems until the most recent updates to 1.86.0

Note: I tried many options like disabling GPU acceleartion, hardware acceleration, and anything i could find from searching for this issue.

Diagnostic data

• Python version (& distribution if applicable, e.g. Anaconda): 3.8.18
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Default

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

XXX

User Settings

languageServer: "Pylance"

Extension version: 2023.25.10292213
VS Code version: Code 1.85.2 (8b3775030ed1a69b13e4f4c628c612102e30a681, 2024-01-18T06:40:32.531Z)
OS version: Darwin x64 21.6.0
Modes:

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz (8 x 2500)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled
Load (avg)	1, 2, 2
Memory (System)	16.00GB (0.04GB free)
Process Argv	--crash-reporter-id 176f9fb8-6147-483c-8438-c8dec2a25aa9
Screen Reader	no
VM	0%

A/B Experiments

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pythontestfixt:30902429
pythonregdiag2:30936856
pyreplss1:30897532
pythonmypyd1:30879173
pythoncet0:30885854
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[anthonykim1]

Hello, @julianghadially thank you for filing this issue. So are you saying you are not able to go back to previous line of 'multi-line' command written in REPL? If that's the case, I'm not sure if I can repro that (See attached)

As far as " I need a way to send multi-line blocks to the terminal line-by-line (e.g., using shift-enter). "
You may explicitly highlight/select part/line of the multi-line block that you wish to learn and shift+enter to only send those highlighted/selected parts to the REPL.

Screen.Recording.2024-02-09.at.2.51.17.PM.mov

[julianghadially]

Looking at your video, you've replicated the exact situation, but with my environment, the rendered cursor stops when it reaches the leftmost part of the line, but the true cursor continues. So from then on the edit location displayed to me is not actually the true edit location.

Is there any other information you need to resolve this?

[BharatRaviIyengar]

I also have the same problem. When I type a long line in REPL the cursor moves to first position in the screen (even before the shell prompt) and overwrites the existing line. Of course this is only a visual rendering issue and the actual command works fine.

[adunmore]

I am experiencing something similar. However, it happens every time I launch a terminal with "Python: Run Selection/Line in Python Terminal". The cursor displays 47 characters ahead of the position I'm editing. It's very disruptive.

Solutions I've tried:

• disabling python extension shell integration
• switching terminals (happens on both bash and zsh)
• disabling integrated terminal gpu acceleraction
• toggling many other unrelated settings in the Python extension

[adunmore]

I just did some testing. This issue appears to start with version 2024.0.0 of the extension. That's the first version where it happens to me. It does not occur when I'm using version 2023.22.1.

[anthonykim1]

I am experiencing something similar. However, it happens every time I launch a terminal with "Python: Run Selection/Line in Python Terminal". The cursor displays 47 characters ahead of the position I'm editing. It's very disruptive.

This should be fixed now. Its coming from cpythn3.13 python/cpython#126131

[anthonykim1]

@julianghadially are you still suffering from this on the latest insider version of VS Code?

[anthonykim1]

Also wondering if its people are able to repro outside of Python REPL in terminal. Do typing other long commands in VS Code terminal repro the problem?

[adunmore]

I am experiencing something similar. However, it happens every time I launch a terminal with "Python: Run Selection/Line in Python Terminal". The cursor displays 47 characters ahead of the position I'm editing. It's very disruptive.

This should be fixed now. Its coming from cpythn3.13 python/cpython#126131

Yes it's fixed now. Thanks.