@Tihiy Hello, we'd like to report a problem we've encountered.
Under normal use, after an unknown period of time, we've noticed that hovering the mouse cursor over applications in the taskbar no longer displays preview thumbnails.
However, hovering the mouse cursor over an application while simultaneously opening the Start Menu (using the Windows key) will display the application's preview thumbnail.
In this situation, right-clicking on a preview thumbnail and moving the mouse displays preview thumbnails for other applications in the taskbar.
But clicking anywhere else on the screen and then moving the mouse back to an application in the taskbar no longer displays preview thumbnails.
The following video is a test example: