In my case, I wanted the horizontal mousewheel to work inside of Visual Studio.
This hack works, except for me with the MX Master 3 mouse I had to use Ctrl+Opt+(right arrow) and Ctrl+Opt+(left arrow) to make this work. Only horizontal scrolling with an ICA session isn't working, but is with an RDP session.
I can't find any citrix documentation that either says side scrolling supported or not and I can't phantom that it wouldn't be supported basic feature without the need for special drives (my tested logitechs are basic HID devices - Mac trackpad I kinda get because everything apple peripherals on windows client is like a snowflake device.) Vertical scrolling works fine from all my tested devices without special drivers installed the VDI. I've even tried to remove the default blacklisted pid/vid from the workspace client to forcefully directly connect a mouse with the session, but that "unplugs" it from the client computer as expected so it becomes non functional. Both works fine without drivers installed with the native windows rdp client from windows and mac clients to the exact same VDI machine so the signal is being sent and emulated and since citrix is (roughly) a layer on top of terminal services it's werid to see it not working by default. I wondered the same about side scrolling with multiple logitech mouse wheels from windows client and macbooks track pad from a macbook. To get flair with your certification level send a picture of your certificate with your Reddit username in the picture to the moderators.
XenApp Printer Driver Manager - Print Driver Management for XenApp 6.x