[v1.1.9] How to fix the conflict with module Cart2Quote?

Issue:

Magento 2 Pre Order was working well until we found out that it is not compatible with Cart2Quote. We couldn't view the Quotation of module Cart2Quote in the admin.

Solution:

Pre Order module and Cart2Quote module both use the same block 

Magento\Sales\Block\Adminhtml\Items\Column\DefaultColumn

which causes a conflict between them.

To solve this conflict, we have changed this file app/code/Bss/PreOrder/Plugin/BackendNotice.php

Please check and apply this fixed file on your site.

If you have any issues, please feel free to contact us.

We'd like to help.