New misspellings found, please review:

• Definiation

perl -e '
my @expect_files=qw('".github/actions/spell-check/expect/af1ff90dc512c83c902762b02f284c1c61603b4a.txt
.github/actions/spell-check/expect/alphabet.txt
.github/actions/spell-check/expect/expect.txt
.github/actions/spell-check/expect/web.txt"');
@ARGV=@expect_files;
my @stale=qw('"Autogenerated Inplace notypeopt Textbox "');
my $re=join "|", @stale;
my $suffix=".".time();
my $previous="";
sub maybe_unlink { unlink($_[0]) if $_[0]; }
while (<>) {
  if ($ARGV ne $old_argv) { maybe_unlink($previous); $previous="$ARGV$suffix"; rename($ARGV, $previous); open(ARGV_OUT, ">$ARGV"); select(ARGV_OUT); $old_argv = $ARGV; }
  next if /^($re)(?:$| .*)/; print;
}; maybe_unlink($previous);'
perl -e '
my $new_expect_file=".github/actions/spell-check/expect/82b6fce5782662b7bbc35802ead5811682566c0a.txt";
open FILE, q{<}, $new_expect_file; chomp(my @words = <FILE>); close FILE;
my @add=qw('"autogenerated Definiation inplace textbox "');
my %items; @items{@words} = @words x (1); @items{@add} = @add x (1);
@words = sort {lc($a) cmp lc($b)} keys %items;
open FILE, q{>}, $new_expect_file; for my $word (@words) { print FILE "$word\n" if $word =~ /\w/; };
close FILE;'
git add .github/actions/spell-check/expect || echo '... you want to ensure .github/actions/spell-check/expect/82b6fce5782662b7bbc35802ead5811682566c0a.txt is added to your repository...'

⚠️ Reviewers

At present, the action that triggered this message will not show its ❌ in this PR unless the branch is within this repository.
Thus, you should make sure that this comment has been addressed before encouraging the merge bot to merge this PR.

For those curious for a preview:

Note that my ubuntu profile has acrylic pretty agressively enabled. What is important:

• the pane's title color reflects the control "tab color" (or title color).
• The tab reflects the focused pane's "title color" and "title text". So selecting the "foo" pane changes the tab text to "foo", and the tab color to purple, while selecting the "cmd" pane changes the tab color to the default black, and the tab text to "cmd".
• this looks awesome with focus mode:
  
• Maybe the default pane titlebar color should be the same as the focused tab item background? That might lead to more consistency with the UX when a pane has a title color

re:

Currently, setting the tab's background color with the color picker does not update the pane titlebar color.

I think that's fine. Currently, the order of precedence is [tab runtime color, control title color, theme color (unimplemented), default color]. So I could imagine this going two ways:

• convert the "tab runtime color" to be a "pane runtime color". Then, using the color picker on the tab would set the active pane's runtime color. This comes with the detrimental side effect that you'd have to re-color each pane in a tab manually.
• add an additional "pane runtime color", and have the tab's color be composed from [tab runtime color, pane color (which is itself [pane runtime color, control title color, theme pane title color]), theme color, default]. This would allow panes to have their color changed at runtime with a color picker, and also have the tab have a manual color override.

I'm of course just hypothesizing here in the comments - I don't think any of this is something that needs to get done in this PR. We can always loop back on the issue in a follow-up.

So, here's a quick update. I fixed some of the comments above, however, the issue regarding a crash after a child pane is closed still exists and I have not been able to find a fix in my free time. This maybe held up by #3999?

Just wanted to get this back into the spotlight in case it got lost in the pile of other feature requests / issues. I know you showed some interested in this feature @DHowett, so would you mind also taking a look at some of the code here and maybe provide some insight. I didn't want to bother @zadjii-msft since he is out. Let me know what you think!

As much as I want this feature done as quickly as possible, I would rather us do the harder work up front so additions to the Pane titlebar and Pane itself are easier. In this case I agree that this PR should be blocked until there is a better solution like you provided. I would be up for helping rework some of it, but I have been busy recently.

In this case I agree that this PR should be blocked until there is a better solution like you provided. I would be up for helping rework some of it, but I have been busy recently.

I'll close this for now, but not as a rejection. This is a sound idea that we'll revisit when we can support it best 😄

Thanks so much for doing the lifting here.