So I've figured out the issue, it seems to come down to how Firefox is handling the URL in the first place. This has been tested with the Horizon 4.8.x and 4.10.x clients and Firefox v64.0. Both are 64bit versions, running on Ubuntu 18.04.1
- Download the client from the VMWare Horizon Client for 64-bit Linux
- In Firefox, open about:config and click through the warning.
- Add a new boolean entry called network.protocol-handler.expose.vmware-view and set the value to false
- Create a file called `test.html` somewhere on your computer and put the following in it:
<html><a href='vmware-view://example.com'>test</a></html> - Open the file in Firefox and click on the link, which should prompt you for a path to open the link.
- Select /usr/bin/vmware-view and it should work for future uses!
I owe a workmate lunch now