[Tooltip] must be as child of ToggleButton

[FabriceSalvaire]

Using @material-ui/lab": "^4.0.0-alpha.56

In the doc https://material-ui.com/components/tooltips/ there is this example

<Tooltip title="Delete">
  <IconButton aria-label="delete">
    <DeleteIcon />
  </IconButton>
</Tooltip>

But with this code, the second button is not styled as checked when we click on it

<ToggleButtonGroup>
    <ToggleButton></ToggleButton>
    <Tooltip title="">
        <ToggleButton>
            <span></span>
       </ToggleButton>
    </Tooltip>
</ToggleButtonGroup>

a workaround is to place the tooltip as a child of ToggleButton

<ToggleButtonGroup>
    <ToggleButton></ToggleButton>
    <ToggleButton>
        <Tooltip title="">
            <span></span>
        </Tooltip>
    </ToggleButton>
</ToggleButtonGroup>

[oliviertassinari]

Duplicate of #18091