Windows Magnifier not following text caret when accessibility support is enabled

• VSCode Version: Code 1.48.2 (a0479759d6e9ea56afa657e454193f72aef85bd0, 2020-08-25T10:13:11.295Z)
• OS Version: Windows_NT x64 10.0.19041

Steps to Reproduce:

1. Launch VSCode and make sure accessibility support is enabled. 2.open/create a file. The file should be on multiple lines with decent length of lines. IE settings.json.
2. Launch magnifier, and ensure that it is set to follow the text cursor.
3. Try to navigate the file without editing it (IE with just the arrow keys).

Expected behaviour

• Magnifier should follow the caret as it moves.

Actual behaviour

• Magnifier may initially follow the caret, but will drift away from it over time.
• Inserting new characters seems to reset the detected caret position to the actual one, but deleting characters doesn’t.

I conjecture that this is because the textbox used for the accessible editor isn’t properly syncronised with the displayed editor, but I’m not familiar enough with the internals to know for sure.

There are a number of closed issues for this bug, but, testing both in stable and nightly, I am still experiencing it.

Does this issue occur when all extensions are disabled?: Yes

[isidorn]

Thanks! Created a follow up issue https://github.com/microsoft/vscode/issues/164591

[isidorn]

@alexdima I can look into all the changes and do some bisection.