Setting for negativeTabIndex has no effect

[Toni-D1]

I'm submitting a...

• Bug report

The setting for negativeTabIndex does not change the tab Index setting for the buttons, this is always -1.
This feature was added here #24

Reproduction steps

See this JSFiddle: https://jsfiddle.net/s62m4gor/
Changing negativeTabIndex does not change the resulting tabIndex of the bold button.

Version information

Browser type and version: Chrome 116.0.5845.110 / Safari 16.6 (18615.3.12.11.2)
InscrybMDE version: 1.11.6

Thanks for the help.