Combobox in fluent ui panel shows no checked values

[dbahnms]

Hi everybody,

I´m not sure if it´s a bug or a feature:
I want to use a combobox inside of a panel.
"@fluentui/react": "^8.120.9",
node: 'v18.20.4', npm: '10.8.1'

<ComboBox className={ styles.combobox }
label="Filter"
multiSelect
options={this.state.filteroptions} // any[]
selectedKey={this.state.selectedKeys} // string[]
onChange={this._onSelectedFiltersChangeNew.bind(this)}
/>

I´m able to select the filteroptions and the filter is used correctly but the checkbox is not checked.

If I close the panel and open it again the state is selected and it looks good:

It is possible to force an additional update?