You can isolate the app icons in the taskbar or dash/dock – based on what workspace or monitor they're on – by opening the Zorin menu > Settings > Multitasking and scrolling to the bottom to reach the "Application Switching" settings.
Based on this thread – and other similar reports recently – we've made it easier to find this settings. We released a software update to the Zorin Taskbar a few days ago to add a link to these Multitasking options in the Taskbar Settings window:
