Dropdown autowidth is not working when it used inside the TabView

[udithaindika]

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[X] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see http://forum.primefaces.org/viewforum.php?f=57

Plunkr Case (Bug Reports)
https://plnkr.co/edit/gc5ndj?p=preview](https://plnkr.co/edit/gc5ndj?p=preview
https://codesandbox.io/s/zq80v2j6ox

Current behavior
When a Dropdown is used inside a non active TabPanel of a TabView, the Width of the DropDown is not properly set.

Expected behavior
Dropdown width should set regardless of the TabPanel its being used.

Minimal reproduction of the problem with instructions

1. Create a TabView
2. Add Two TabPanels to the TabView
3. Add the Same Dropdown to both these TabPanels(see following JSX)
4. When view this in the Browser , Dropdown in the First Tab have the proper Width
5. Dropdown in the second Tab don't have the proper width(width is about 30px)

<TabView>
    <TabPanel header="Tab1">
      <Dropdown
        options={citySelectItems}
        placeholder="Select a City"
        autoWidth={true}
      />
    </TabPanel>
    <TabPanel header="Tab2">
      <Dropdown
        options={citySelectItems}
        placeholder="Select a City"
        autoWidth={true}
      />
    </TabPanel>
</TabView>

Please tell us about your environment:
Windows,Webstorm, NPM, Webpack-dev-server

React version: React v.16.2

PrimeReact version: PrimeReact v 1.5.0

Browser: [all]

Language: [ES6/7]