Some errors in docs

[josefpihrt]

Hello,

First of all I would like to say that your documentation is very good and thorough.

Nevertheless I encountered some minor issues:

1. RangeSlider looks weird in the example here: https://www.dotvvm.com/products/dotvvm-business-pack

2. It is not possible to finish last tutorial in the academy "Basic validation". During the last but one step the there is an error (even if the user clicks "Show solution").

3. Page "Access validation errors from JS" is empty.

https://test.dotvvm.com/docs/4.0/pages/concepts/client-side-development/access-validation-errors-from-js

I used latest Chrome browser.