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## Summary of the Pull Request
This sets the tab close button color to match the tab text color.
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## References
#8046
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## PR Checklist
* [x] Closes#8046
* [x] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [ ] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #8046
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## Detailed Description of the Pull Request / Additional comments
This sets the tab close button color to match the tab text color.
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## Validation Steps Performed
Test light theme white tab mouse hover effect:
Test dark theme white tab mouse hover effect:
In preparation for the Settings UI, we needed to make some changes to
Tab to abstract out shared, common functionality between different types
of tab. This is the result of that work. All code references to the
settings have been removed or reverted.
Contains changes from #8053, #7802.
The messages below only make sense in the context of the Settings UI,
which this pull request does not bring in. They do, however, provide
valuable information.
From #7802 (@leonMSFT):
> This PR's goal was to add an option to the `OpenSettings` keybinding to
> open the Settings UI in a tab. In order to implement that, a couple of
> changes had to be made to `Tab`, specifically:
>
> - Introduce a tab interface named `ITab`
> - Create/Rename two new Tab classes that implement `ITab` called
> `SettingsTab` and `TerminalTab`
>
From #8053:
> `TerminalTab` and `SettingsTab` share some implementation details. The
> close submenu introduced in #7728 is a good example of functionality
> that is consistent across all tabs. This PR transforms `ITab` from an
> interface, into an [unsealed runtime class] to de-duplicate some
> functionality. Most of the logic from `SettingsTab` was moved there
> because I expect the default behavior of a tab to resemble the
> `SettingsTab` over a `TerminalTab`.
>
> ## References
> Verified that Close submenu work was transferred over (#7728, #7961, #8010).
>
> ## Validation Steps Performed
> Check close submenu on first/last tab when multiple tabs are open.
>
> Closes#7969
>
> [unsealed runtime class]: https://docs.microsoft.com/en-us/uwp/midl-3/intro#base-classes
Co-authored-by: Carlos Zamora <carlos.zamora@microsoft.com>
Co-authored-by: Leon Liang <lelian@microsoft.com>
Co-authored-by: Carlos Zamora <carlos.zamora@microsoft.com>
