2.2: Buttons Checkbox example
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**Primary Actor**: User

**Scope**: Ngx-bootstrap DEMO / BS version 3&4

**Goal**: Show user checkbox-like buttons example

Main success scenario:
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1. User opens Buttons demo page
2. User clicks on Checkbox sub-menu
3. User see button-group, contain of 3 parts(labels)
4. By default, 1st button is inactive, 2d - active and 3d - inactive
5. User able to click on each button
6. When user clicks on the inactive button, it become active
7. User can make all buttons inactive and can make all buttons active

Variations:
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2*. User scrolls to Checkbox sub-menu