Problems with Visual Studio Code Editor

[shaker]

I hope that this is an appropriate palce for ask the question below. If
not, I would appreciate getting a pointer to an appropriate group.

While using the Visual Studio Code Editor, I somehow accidentally
managed to turn on the display of formatting marks (such as tabs and
spaces). In other words, my source code shows each space as a period
and each tab as an ->.

I am wondering whether someone can tell me how to turn this off. I
didn't see a way of doing this under Tools->Options.

Thanks.

Shaker