If you're on the latest beta of GitHub Actions, there's a drop-down for re-running all checks that you can't click.
I can confirm that it works fine on Firefox and in Chrome after I've disabled the extension.
Example URL — https://github.com/paambaati/websight/pull/10/checks?check_run_id=193115347
Screenshot of the dropdown in question (from Firefox)

CSS selector
details.dropdown:nth-child(1) > summary:nth-child(1)
Markup
<div>
<details class="dropdown details-reset details-overlay d-inline-block ml-4 mt-n1" open="">
<summary class="btn btn-sm" aria-haspopup="true">
<svg></svg>
Re-run checks
<div class="dropdown-caret"></div>
</summary>
<template id="js-check-suite-rerequest-form-success">
<div class="flash flash-full flash-notice">
<div class="container">
<button class="flash-close js-flash-close" type="button" aria-label="Dismiss this message">
<svg></svg>
</button>
You have successfully requested checks from GitHub Actions.
</div>
</div>
</template>
<template id="js-check-suite-rerequest-form-error">
<div class="flash flash-full flash-error">
<div class="container">
<button class="flash-close js-flash-close" type="button" aria-label="Dismiss this message">
<svg></svg>
</button>
There was a problem requesting checks from GitHub Actions.
</div>
</div>
</template>
<ul class="dropdown-menu dropdown-menu-sw" style="width: 170px">
<li>
</li>
<li>
<input type="hidden" name="only_failed_check_runs" value="false">
<button class="dropdown-item btn-link" type="submit">
Re-run all checks
</button>
</form> </li>
</ul>
</details>
</div>
What's its container? Is it inside .pr-toolbar?
@fregante It is, yes.
Had a chance to test this, it looks like close-out-of-view-modals is the culprit.

GitHub uses some <template> tags for internal UI use, that which https://github.com/sindresorhus/refined-github/blob/372e282cfd2e207704e99c4b4538e110b4a4d1a4/source/features/close-out-of-view-modals.tsx#L16 picksup, <template> tags are display: none by default, causing them to report as "out of view" in this case.

Out of context, GitHub should provide an option to re-run tests (individually if possible) for recent comments and PR that pass too, not just for PRs that have failed steps.
I don't who to ping about this, so pinging @lukehefson as a start.
Not GitHub’s fault here, the feature should look for other siblings of summary, I suppose, that are not template
PR welcome