p-dropdown only sets filled on click, not on select (doesn't work with keyboard)

[scrimothy]

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Plunkr Case (Bug Reports)
https://stackblitz.com/edit/github-xvghjz

Current behavior
If you click an option in the p-dropdown, it will set filled = true, however, if you select an option by any other means (programmatically, or with a user keyboard), filled is not changed.

Expected behavior
filled should be set to true no matter how the value gets set, not just by clicking an item.

Minimal reproduction of the problem with instructions

1. Click (or tab and use space key) to open dropdown options overlay
2. Use down arrow to select the option you want
3. Use enter key to select the option
4. See that filled is not changed, but the value is

What is the motivation / use case for changing the behavior?
If using a Material-like theme (like Ultima) which uses floating labels, if a user uses their keyboard to select an option, the label never moves out of the way of the value, so the two will overlap each other in the component.

Please tell us about your environment:
Operating system: MacOS
IDE: VS Code
package manager: NPM
HTTP server: ng serve

• Angular version: 7.X
  still an issue in 8 (see stackblitz)

• PrimeNG version: 7.X
  still an issue in 8 (see stackblitz)

• Browser: all

• Language: all

[mertsincan]

Thanks a lot for the solution!

Best regards,