Multi Selection Combobox flashing on option selection

[kkdash1]

This is a bug report for the @clr Angular or UI versions of the design system. For the web-component implementation of Clarity (@cds), visit vmware-clarity/core.

Describe the bug

Mutli Selection combobox has a flashing issue each time an option is selected

How to reproduce

https://stackblitz.com/edit/clarity-light-theme-clr12-cds5-ekgaxb?file=package.json,src%2Fapp%2Fapp.component.html,src%2Fapp%2Fapp.component.ts

https://vmware.slack.com/archives/C0JF8D2LB/p1657302054855429?thread_ts=1631554938.257800&cid=C0JF8D2LB

Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior

There should be no flashing

Versions

Clarity version:

• [x] v12.x
• [ ] v13.x
• [ ] Other:

Framework:

• [x] Angular
• [ ] React
• [ ] Vue
• [ ] Other:

Framework version: ie: Angular 12

Device:

• Type: [MacBook]
• OS: [iOS]
• Browser [chrome]
• Version [103.0.x]

Additional notes

Add any other notes about the problem here.

[Jinnie]

The flashing is caused by Opacity change, which conceals a much worse live repositioning of the smart popovers. Possible fixes would be to:

• Change the current popovers implementation used. The one from Core is a good candidate.
• Try to make sure the opacity change is only applies if a repositioning will really occur.