Use standard 1px window borders on NC Island Window

[beviu]

Summary of the Pull Request

I put the standard Windows window borders on the Windows Terminal window (can you read that?).
(It's only on the left, bottom and right though, on the top I had to use a hack because of the title bar)

Light mode, color in title bar disabled:

Light mode, color in title bar enabled:

Dark mode, color in title bar disabled:

Dark mode, color in title bar enabled:

High contrast mode (with Settings app on right to compare):

Note: the title bar should probably be purple like in Win32 apps but it isn't either in the UWP apps (Settings, classic Edge, …) so I don't really know.

References

PR Checklist

• Closes White border at the bottom of the window. #3064, closes Thick white border around window when showTabsInTitlebar enabled #1307, closes Window Border expands when showTabsInTitlebar is enabled #3136, closes Lots of work is duplicated when NonClientIslandWindow is resized and the drag bar size changes #1897, closes Suspicious remains of previous window borders flash up when closing the window #3222, closes Window border width does not respect system theme #1859, closes Maximizing terminal when window is across two monitors causes bars to bleed across monitor. #2268 and maybe more?
• CLA signed. If not, go over here and sign the CLA
• Tests added/passed
• Requires documentation to be updated
• 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: #xxx

Detailed Description of the Pull Request / Additional comments

We take the standard window frame except that we remove the top part (see NonClientIslandWindow::_OnNcCalcSize), then we put little 1 pixel wide top border back in the client area using DwmExtendFrameIntoClientArea and then we put the XAML island and the drag bar on top.

Most of this PR is comments to explain how the code works and also removing complex code that was needed to handle the weird cases when the borders were custom.

I've also refactored a little bit the NonClientIslandWindow class.

Validation Steps Performed

[beviu]

With this change there is no resize handle directly on top of the tab row. This is the same behavior as classic Edge for reference (but it doesn't mean that it's good). This might be fixed by adding space on top of the tab row and excluding it from the XAML island region.

[miniksa]

I don't know enough about the non-client area and XAML stuff to go through this. @DHowett-MSFT is the non-client expert and @zadjii-msft is the current UI king. So I'll let them stab first.

[musm]

bravo!

[ghost]

🎉Windows Terminal Preview v0.7.3291.0 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Store Download

[Stanzilla]

So...any way to color this new 1px border? I don't think there is a setting in Windows to color inactive window borders differently anymore, is there?

[adrianghc]

I'd be most comfortable merging this without the dark theme fix (which I know will cause there to be white borders around the entire window instead of just at the bottom) and then bringing in the dark theme changes when the other fix has flowed back down from Windows.

I couldn't find more details about this here, so does this mean the white border will be fixed with a new release or does the fix need to come from Windows, i.e. we would have to get 20H1 for the fix?

[beviu]

@Stanzilla The border behaves the same way as other windows. When it is active it will be either the accent color that you chose in Windows Settings if "Show accent color on the following surfaces -> Title bars and windows borders" is checked or a gray color otherwise. When it is inactive, it will always be gray. I don't think that there is a setting to color inactive window borders in Windows.

@adrianghc 20H1 changed the way to make the border dark. I think it is possible to detect if 20H1 is running and use the new way and if it's older than 20H1, use the old way to make the border dark so it could be fixed without waiting for 20H1 if this is done.

[Stanzilla]

Well yeah, I don't really want to use my accent color on every window, was just wondering if there is a way to overwrite. But if that is black in 20H1 I'm okay with that

[danielniccoli]

In addition to the bottom white border, I now have 3 more borders, making the issue officially 4 times worse 😂

[michaelhthomas]

Yes indeed, the border in dark mode is still white I've noticed, which is quite bothersome to look at.

[Bebotron]

Version 0.9 has rolled out and my Windows Terminal still has this problem. Any ideas as to what the status of this issue is?

[beviu]

Yes, see #3425 and maybe PR #4577.

[Bebotron]

Thanks @greg904, so it sounds like its not a stable solution yet correct? Wondering if it might be best to sit tight a little longer until a new version of WT fixes this, or if it's worthwhile to attempt your solution in #4577

[beviu]

If you run the fix:

• you are running the dev or master version which is not stable and can have bugs
• on top of it you are running my fix which is not very tested (I made it quickly because I, too, want that bright border to go away :))

If you wait:

• last release was 2 days ago so I'm guessing the new release won't come in a few days
• maybe more stable

BTW, just to be clear:

With the fix, if you disable:

You get this:

And if you enable it, you will have a border but now it will be blue:

So there still is a blue border but it is just like other apps: