I cannot say definitively whether this is a bug or not but I'll explain what's happening. If you follow these steps in VS, you will find that when the pane is unpinned focus is shifted to another pane. So when you hover back over that tab, the flyout will hide when the mouse leaves the bounds. If you were to click on the unpinned tab or explicitly give focus to the tab (clicking within it or using a shortcut key to show it - e.g. F4 for properties) the unpinned pane will be activated and the flyout will remain in view regardless of where the mouse is until you move focus to another area of VS or if you hover over another unpinned tab. With the latter scenario, the now flown in pane is still active and if you were to hover over its unpinned tab, it will flyout and remain in view regardless of where the mouse is. We follow this same pattern with one variation. When the pane is initially unpinned, we are not shifting focus to another pane so when you hover back over the pane, it is still the active pane and as such will remain flown out until focus shifts elsewhere within the window or until you hover over another unpinned tab. I could see the point that the focus should be shifted to another pane when the pane is initially unpinned since it is no longer in view and the user may not realize that it still has the input focus so I would recommend submitting this to the support group.