Jan Kučera

Switch is my least favorite option, we keep piling (often unnecessary) switches and never remove them. I am also not quite sure how switch would achieve a feature to be...

There is two different types of additions. One are appearance based (corner radius, backgrounds etc.), one are function based (placeholder text, editing style etc.). Perhaps these could be two different...

Wouldn't `PlaceholderText` be better on `TextBoxBase`?

While I appreciate that depending on the implementation it might be more challenging to get it working for `RichTextBox`, I wonder whether putting it on `TextBoxBase` and implementing it later...

@dipeshmsft do you have an implementation in mind that you could point to or describe? If it was an object, you can just have a `ContentPresenter` in the template which...

What is the A11y point coming up? Does it apply now when we don't support any placeholder, or when developer does not set any? Developers can break A11y in any...

By the way the example with stackpanel and textblocks can be done using textblock and runs. I was going to put in some more scenarios in case that helps convincing...

Perhaps we should keep this issue for the public API changes approval and open issues for the implementations?

`PlaceholderVisible` is unclear. Either it is read-only in which case it should be `IsPlaceholderVisible` or it is settable, in which case `PlaceholderVisibility` of type `Visibility` would be better (and easier...

Disclaimer: I haven't gone through the PR. However, I am worried about the asserts being removed, presumably they were added for a reason and express an expectation of the code...