When dragging a connection tab (e.g. to reorder), both the tabs in that tab panel bar and the icons in the Windows 10 notification area shift left/right rapidly, thus creating a flicking effect.
The longer you hold down the mouse button after initiating dragging, the longer the flickering is going to occur after you release the mouse button.
To reproduce, simply open two or more connections in the same panel and then click and drag one of the tabs left or right.
Intel Core i3
8 GB RAM
Windows 10 Pro