To resolve this issue until a patch is pushed to Citrix Follow the below steps.
Please click the windows icon at the bottom left of the monitor. Begin typing the words “Control Panel” (capitalization not important). Once search has found the application click on the listing.
Select Programs
Select “Default Programs”
Select “set your default programs”
Select Outlook and click “Set this program as default”
The screens will flash and you can press “okay”. The setting will now be engaged and clicking email addresses on websites will open outlook new messages.