I have an 'issue' with Office Integration and non-MS browsers with our SharePoint 2013 on-prem enviroment (using SSO via ADFS).
Background: our internal client wants to move to SharePoint sites for collaboration with external partners. One of the selling points they're wanting to make to justify the move from their current external collaboration site is Office integration - specifically the ability to open/edit/save documents by clicking on the document in SharePoint, having it open in Office (PC/client) for editing. Note they are wanting full integration with the client version of Office - not OWA. The other requirement is that this work with both Firefox and Chrome.
Issue: Office integration works fine using Internet Explorer. When a user click on a document the document opens in Office and can be edited directly in the browser without any additional prompts. But when clicking on a document via Firefox or Chrome the SSO login form pops-up when Office starts. Once the user enters their credentials they can work with the documents as desired. But our client does not want this second prompt.
Question:
Is there a way to configure SharePoint so that Firefox or Chrome open up documents for editing without a second logon prompt? I'm assuming not based on my research on how these browsers handle cookies differently than IE. Can someone confirm?
Is there a dev solution to this? Note that because the users will be partners (non-employees) we are trying to avoid using a solution that would involve installing custom software on their pc's (such as browser extensions).