10.3: Progressbar stacked example
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**Primary Actor**: User

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

**Goal**: Show user stacked progressbar example

Main success scenario:
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1. User open Progressbar demo page
2. User click on Stacked sub-menu
3. User see 1 progressbar with 4 bars inside and "Randomize" button
4. When user click "Randomize", then value of each bar changed
5. Each bar should have appropriate percentage

Extentions:
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4*. When user click "Randomize", then amount of bars inside could be less than 4

Variations:
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2*. User scroll to Stacked sub-menu