• .NET Core Version:
  .Net 6.0 SDK build: 6.0.100-Preview.4.21180.17
• Have you experienced this same bug with .NET Framework?:
  No, framework is not supported TabPage's keyborad tooltip
• More Info

1. This is a regression issue, found after the fix of PR: Adding the ability to get keyboard toolTips for TabPages of a TabControl #4421
2. This issue cannot repro if don't do following step4

Repro steps:

1. Create a Winforms .Net Core app
2. Add a TabControl, a Tooltip, a Button to form designer
3. Focus on TabControl, go to Properties window, set TabControl's ShowToolTips as True, then set TabControl's Tooltip on toolTip1 property as "TabControl", set Tabpages' TooltipText with "TabPage1" and "TabPage2"
4. Set anther control: button's Tooltip on toolTip1 property as "button1" --- it is necessary step
5. Build and run app

Or open attached application:
WinFormsApp12.zip

Actual behavior:
Keyboard to focus on Button, then Tab to Tabpage1, then mouse-over Tagpage2 to show mouse tooltip, Tabpage2 display is not correct: Tabpage2 tooltip shows TabControl's

Expected behavior:
Tabpage2 shows "TabPage2" tooltip