Using actions in dropdown menu adds duplicate list items
The HTML when you load the page.
<menu class="menu">
<li>
<button class="btn-post-action"
data-ic-put-to="https://tildes.net/api/web/topics/kjr/bookmark"
data-ic-replace-target="true"
data-ic-src="https://tildes.net/api/web/topics/kjr/bookmark"
data-ic-verb="PUT" data-ic-trigger-on="default" data-ic-deps="ignore"
data-ic-id="4">Bookmark</button>
</li>
<li>
<button class="btn-post-action" name="topic-actions-ignore"
data-ic-put-to="https://tildes.net/api/web/topics/kjr/ignore"
data-ic-replace-target="true"
data-ic-src="https://tildes.net/api/web/topics/kjr/ignore"
data-ic-verb="PUT" data-ic-trigger-on="default" data-ic-deps="ignore"
data-ic-id="5">Ignore this post</button>
</li>
</menu>
The HTML when you ignore the post.
<menu class="menu">
<li>
<button class="btn-post-action"
data-ic-put-to="https://tildes.net/api/web/topics/kjr/bookmark"
data-ic-replace-target="true"
data-ic-src="https://tildes.net/api/web/topics/kjr/bookmark"
data-ic-verb="PUT" data-ic-trigger-on="default" data-ic-deps="ignore"
data-ic-id="4">Bookmark</button>
</li>
<li>
<li>
<button class="btn-post-action btn-post-action-used"
name="topic-actions-ignore"
data-ic-delete-from="https://tildes.net/api/web/topics/kjr/ignore"
data-ic-replace-target="true"
data-ic-src="https://tildes.net/api/web/topics/kjr/ignore"
data-ic-verb="DELETE" data-ic-trigger-on="default" data-ic-deps="ignore"
data-ic-id="108">Unignore this post</button>
</li>
</li>
</menu>
The HTML when you unignore the post after ignoring it.
<menu class="menu">
<li>
<button class="btn-post-action"
data-ic-put-to="https://tildes.net/api/web/topics/kjr/bookmark"
data-ic-replace-target="true"
data-ic-src="https://tildes.net/api/web/topics/kjr/bookmark"
data-ic-verb="PUT" data-ic-trigger-on="default" data-ic-deps="ignore"
data-ic-id="4">Bookmark</button>
</li>
<li>
<li>
<li>
<button class="btn-post-action" name="topic-actions-ignore"
data-ic-put-to="https://tildes.net/api/web/topics/kjr/ignore"
data-ic-replace-target="true"
data-ic-src="https://tildes.net/api/web/topics/kjr/ignore"
data-ic-verb="PUT" data-ic-trigger-on="default" data-ic-deps="ignore"
data-ic-id="111">Ignore this post</button>
</li>
</li>
</li>
</menu>
As you can see each time you use the action it inserts <li><button ...></li>
into the already existing <li/>
.