Please notice that such ordering plugins, only work when the overview is not filtered or sorted in any way.
Without our plugin, I suspect that it also does not work when you search for a specific post, which is basically the same principle.

As a workaround, you can probably create a new column set in our settings page and click on the ‘restore columns’ link to make it behave as a default overview page. The key here is not to save your column settings, once you clicked on the ‘restore columns’ link. When you want to reorder your posts, you can switch to that overview.