I'm using Windows 11 latest update, Vscode latest version, Python version 3.13.3, I'm using pip and vrtualenv, not uv. I don't use uv. I have ruff extension and pylance extensions for Python installed.

To reproduce this bug

1. Create a python project A, with virtualenv and install some dependencies, and set VScode to use the virtualenv you created by changing the Python interpreter in Vscode.

2. Create a python project B, with virtualenv and install some different dependencies, and set VScode to use the virtualenv you created by changing the Python interpreter in Vscode.

3. close all Vscode instances

4. Open now project A in VSCode, everything works fine

5. Keep project A open, create a new vsode window, ctrl + shift + n then open project B

Now you'll notice Vscode complaining about some pip dependencies missing from project B, that's simply because vscode is still connected to project A virtualenv, you'll have to switch the interpreter for project B manually by selecting the correct virtualenv.