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

• VS Code Version:
• OS Version:

Steps to Reproduce:

1. Have an input on the same page as the editor
2. Type something into the input and reload the page
3. Focus input and select the autofilled option
   
4. The error appears e.getModifierState is not a function

Here you can check it

Error appears in the constructor of StandardKeyboardEvent class as Event is not a KeyboardEvent and doesn't have that method:

The same issue is reported for the Monaco editor but it happens in the vs-code microsoft/monaco-editor#4325