6.16: Dropdowns State change event example
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**Primary Actor**: User

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

**Goal**: Show user example how to subscribe to dropdown state changing events

Main success scenario:
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1. User opens Dropdowns demo page
2. User clicks on State change event sub-menu
3. User see clickable button "Button dropdown"
4. When user clicks on "Button dropdown", then dropdown opened and there are 3 items and card "The dropdown is opened" shown
5. When user clicks on any item, then dropdown closed and card "The dropdown is closed" is shown
6. When user clicks on "Button dropdown" again, then dropdown opened and card "The dropdown is opened" is shown
7. When user clicks on "Button dropdown" again, then dropdown closed and card "The dropdown is closed" is shown

Variations:
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2*. User scroll to State change event sub-menu