Hello,
before the firmware release 4.09.100 it was only possible to use Citrix VDI in a Box 5 thru the XenApp configuration in the IGEL Universal Desktop LX/OS but not with the Firefox browser. Since the 4.09.100 you can also use the firefox browser but:
You need to enable a setting in the registry for this, it’s only mentioned with a short context in the release notes for the 4.09.100 firmware.
Open the IGEL Setup or the UMS profile and go to System->Registry and enable the setting browser_plugin.ica.vdi_fix.
After this configuration the VDI in a Box Webinterface works like a charm for the users.
Cheers
Michael