Form Tabs shows tooltip of last closed Tab

The Form Tabs displays a tooltip relating to the Tab when the user moves the mouse over it.

However, if a tooltip was displayed and then the last form closed, moving the mouse of the Form Tabs would show the tooltip for the Tab that was just closed.

The same could happen when moving the mouse over a Task Pane item that had a tooltip. If the mouse was then moved out of the Task Pane and then back into the Task Pane at the bottom where no items appeared, the previous tooltip would be displayed.