For example, I have FreeTube installed and want to pin that to the Taskbar - I had assumed that I simply searched for it or browse under apps and then right click and a handy option would appear with a selectable 'pin to taskbar'. But apparently not .......... because when I right click on the app a popup menu briefly appear then vanishes!
Right after 17 came out while still in Beta I posted about this problem. I found that some apps would not let me pin them to the Dash/Taskbar. Yet others worked liked I expected. While the app is running you can try to pin it. But when you right click, the option to pin is NOT there. That is one of the reasons I left Zorin. I have a few apps that I use every day. But I couldn't pin a couple of them. As far as I know no one has figured out what the problem is.