Moving focus to an element with no ToolTip opens an ancestor's ToolTip

[SamBent]

• .NET Core Version: 3.0+
• Windows version: all
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes
• Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc...)? no

• Security issues and bugs should be reported privately, learn more via our responsible disclosure guidelines.

  Problem description:

  1. Run sample app from #4612
  2. Press TAB repeatedly to move focus to the TextBox labeled "No tool tip". (It's inside a GroupBox)
  3. Wait 5 sec

  Actual behavior: The GroupBox's ToolTip appears.

  Expected behavior: No ToolTip appears.

Moving keyboard focus to an element should open the element's ToolTip if it has one. It should not open some other element's ToolTip.

[SamBent]

Fixed by the tooltip work in 6.0-preview7.