No longer get hover-scroll buttons from taskbar when too many windows open in an app to fit in list

### Describe the bug I don't know when this started, but I recently noticed that if I have too many windows open in an app, then when I hover over the app's taskbar entry, I no longer get the up and down scroll "button" arrows that I used to be able to hover over to scroll the window list. Those arrows still show and work just fine in the Start menu's "recent programs" list, if I have "Max recent programs" set to more than will fit onscreen. But on the taskbar window list for an app, if I open additional windows beyond the max that will fit onscreen (in the vertical "stack" of textual window names; it isn't doing taskbar previews, when you have that many open), there's no longer any indication that there are additional windows. I don't know if this functionality is something that Open Shell was providing, and a recent(ish?) Windows 11 update broke it, or if this is still basic Windows functionality that MS dropped in an update, and Open Shell would have to reimplement it, or what. Also possibly relevant is that I also run Binary Fortress' DisplayFusion, though only in Free Version mode, where its own Taskbar functionality is not enablable. I originally noticed this in Firefox, as I usually run large sessions, with a whole bunch of open windows (most with multiple tabs, so please don't suggest using tabs instead of multiple windows), but I confirmed that it happens with Edge as well. ### Area of issue Taskbar ### To reproduce 1. Open as many windows in an app as will fit in the vertical text stack of window names. 2. Hover over the app's taskbar entry. 3. Note that all open window names are visible. 4. Open one more window in that app. 5. Hover over the taskbar entry again. 6. Note that the new window is not mentioned, and there are no up/down hover arrows to scroll through the window list. ### Expected behavior Expected the hover arrows, as in the past. ### Open-Shell version 4.4.196 ### Windows version Windows 11 25H2 ### Additional context _No response_