minimize button doesn't have a tooltip

[stevenbrix]

Describe the bug

winui3 applications don't have a tooltip when you hover over the minimize button

Steps to reproduce the bug

Hover over minimize button of a winui3 app

Expected behavior

Screenshots

NuGet package version

WinUI 3 - Windows App SDK 1.4.2: 1.4.231008000

Windows version

Windows 11 (22H2): Build 22621

Additional context

No response

[IviriusMain]

Sending HTMAXBUTTON as a response to WM_NCHITTEST doesn't fix this issue
Maximize/Restore and Close buttons do show tooltips (and/or snap layouts) though

[IviriusMain]

Here, you can see snap layouts show on a custom caption button

Same with the close button's tooltip

But the minimize button shows nothing

This shows it's not an issue with sending HTMINBUTTON as a result to WM_NCHITTEST in the platform's caption buttons.

(WinUI 3, Windows App SDK v1.5.240627000)

[IviriusMain]

Update: this bug seems to only occur when ExtendsContentIntoTitleBar is set to true.