ui5-tabcontainer show overflow popover does not work with namespaced ui5-button

[JarrettChan]

Bug Description

If the ui5-button is namespaced with a suffix, clicking the ui5-button to show the overflow popover does not do anything.

Expected Behavior

ui5-tabcontainer overflow should select ui5-button with a stable selector:
const button = this.overflowButton[0] || this.getDomRef().querySelector(".ui-tc__overflowButton > ui5-button");
please use the pure tag or some equivalent to select the ui5-button

Isolated Example

https://codesandbox.io/s/ui5-webcomponents-forked-30gex

Priority

• Low
• Medium
• High
• Very High

Note: The priority might be re-evaluated by the issue processor.

Stakeholder Info (if applicable)

• Organization: SuccessFactors
• Business impact: blocking adoption of namespaced elements

[JarrettChan]

Attempting to use addCustomCSS across multiple ui5wc cores does not work currently.
To fix from our side would need to either namespace the elements to be able to use addCustomCSS (blocked by this issue) or the other option I'm exploring is manually traversing and inserting a style tag.