Repro steps:
- Create a Winforms .Net Core application
- Add a toolStrip on the form designer
- Add a toolStripDropDownButton on the toolStrip
- Add several drop down items under toolStripDropDownButton
- In the Form.Designer.cs file, edit height of the this.toolStripDropDownButton1.DropDown.MaximumSize property in order to just display one or a part of one drop down item
Or using attached app:
WinFormsApp91.zip
- Build and run app, then click ToolStripScrollDownButton to display the last dropdown item
Actual behavior:
The ToolStripScrollDownButton is still enabled when displaying the last dropdown item, and in this case, an exception pops up when clicking that ToolStripScrollDownButton again


Expected behavior:
When go through the last dropdown item, the ToolStripScrollDownButton is disabled

.NET Core Version:
7.0.100-preview.2.22103.2
Have you experienced this same bug with .NET Framework?:
Yes
Repro steps:
Or using attached app:
WinFormsApp91.zip
Actual behavior:

The ToolStripScrollDownButton is still enabled when displaying the last dropdown item, and in this case, an exception pops up when clicking that ToolStripScrollDownButton again
Expected behavior:

When go through the last dropdown item, the ToolStripScrollDownButton is disabled