Let inline sections take precedence over --header-first

--header-first previously was rejected with --header-border=inline or
--header-lines-border=inline. Now, inline placement wins: an inline
section stays inside the list frame, and --header-first only affects
non-inline sections (mainly the main --header).

man/man1/fzf.1

@@ -1107,9 +1107,10 @@ shape that has both top and bottom segments (rounded / sharp / bold /
 double / block / thinblock / horizontal) and falls back to \fBline\fR
 otherwise. When the list border also has side segments, the separator
 joins them with T-junctions; \fBhorizontal\fR has no side borders, so the
-separator is drawn without T-junction endpoints. Not compatible with
+separator is drawn without T-junction endpoints. Takes precedence over
-\fB\-\-header\-first\fR, and when \fB\-\-header\-lines\fR is also set
+\fB\-\-header\-first\fR (the section stays inside the list frame), and
-\fB\-\-header\-lines\-border\fR must also be \fBinline\fR.
+when \fB\-\-header\-lines\fR is also set \fB\-\-header\-lines\-border\fR
+must also be \fBinline\fR.
 
 .TP
 .BI "\-\-header\-label" [=LABEL]
@@ -1128,7 +1129,7 @@ a single separator line between the header lines and the list section.
 \fBinline\fR style embeds the header lines inside the list border frame
 with a horizontal separator; it requires a \fB\-\-list\-border\fR shape
 that has both top and bottom segments, falls back to \fBline\fR
-otherwise, and is not compatible with \fB\-\-header\-first\fR.
+otherwise.
 
 .SS FOOTER
 

src/options.go

@@ -3619,9 +3619,6 @@ func validateOptions(opts *Options) error {
 		opts.Preview.border == tui.BorderInline {
 		return errors.New("inline border is only supported for --header-border, --header-lines-border, and --footer-border")
 	}
-	if opts.HeaderFirst && (opts.HeaderBorderShape == tui.BorderInline || opts.HeaderLinesShape == tui.BorderInline) {
-		return errors.New("--header-first is not compatible with --header-border=inline or --header-lines-border=inline")
-	}
 	if opts.HeaderBorderShape == tui.BorderInline &&
 		opts.HeaderLinesShape != tui.BorderInline &&
 		opts.HeaderLinesShape != tui.BorderUndefined &&

src/terminal.go

@@ -2844,7 +2844,11 @@ func (t *Terminal) resizeWindows(forcePreview bool, redrawBorder bool) {
 
 	if hasInputWindow {
 		var btop int
-		if (hasHeaderWindow || hasHeaderLinesWindow) && t.headerFirst {
+		// Inline sections live inside the list frame, so they don't participate
+		// in --header-first repositioning; only non-inline sections do.
+		hasNonInlineHeader := hasHeaderWindow && t.headerBorderShape != tui.BorderInline
+		hasNonInlineHeaderLines := hasHeaderLinesWindow && headerLinesShape != tui.BorderInline
+		if (hasNonInlineHeader || hasNonInlineHeaderLines) && t.headerFirst {
 			switch t.layout {
 			case layoutDefault:
 				btop = w.Top() + w.Height()

test/test_layout.rb

@@ -1491,6 +1491,42 @@ class TestLayout < TestInteractive
     tmux.send_keys 'Escape'
   end
 
+  # Inline takes precedence over --header-first: the main header stays
+  # inside the list frame instead of moving below the input.
+  def test_inline_header_border_overrides_header_first
+    tmux.send_keys %(seq 5 | #{FZF} --style full --header foo --header-first --header-border inline), :Enter
+    tmux.until do |lines|
+      foo_idx = lines.index { |l| l.match?(/\A│\s+foo\s+│\z/) }
+      input_idx = lines.index { |l| l.match?(/\A│\s+>\s+\d+\/\d+\s+│\z/) }
+      foo_idx && input_idx && foo_idx < input_idx
+    end
+  end
+
+  # With both sections present, --header-first still moves the main --header
+  # below the input while --header-lines-border=inline keeps header-lines
+  # inside the list frame.
+  def test_inline_header_lines_with_header_first_and_main_header
+    tmux.send_keys %(seq 5 | #{FZF} --style full --header foo --header-lines 1 --header-first --header-lines-border inline), :Enter
+    tmux.until do |lines|
+      one_idx = lines.index { |l| l.match?(/\A│\s+1\s+│\z/) }
+      foo_idx = lines.index { |l| l.match?(/\A│\s+foo\s+│\z/) }
+      input_idx = lines.index { |l| l.match?(/\A│\s+>\s+\d+\/\d+\s+│\z/) }
+      one_idx && foo_idx && input_idx && one_idx < input_idx && input_idx < foo_idx
+    end
+  end
+
+  # With no main --header, --header-first previously repositioned
+  # header-lines. Inline now takes precedence: header-lines stays inside
+  # the list frame.
+  def test_inline_header_lines_with_header_first_no_main_header
+    tmux.send_keys %(seq 5 | #{FZF} --style full --header-lines 1 --header-first --header-lines-border inline), :Enter
+    tmux.until do |lines|
+      one_idx = lines.index { |l| l.match?(/\A│\s+1\s+│\z/) }
+      input_idx = lines.index { |l| l.match?(/\A│\s+>\s+\d+\/\d+\s+│\z/) }
+      one_idx && input_idx && one_idx < input_idx
+    end
+  end
+
   # Invalid inline combinations must be rejected at startup.
   def test_inline_rejected_on_unsupported_options
     [
@@ -1498,8 +1534,6 @@ class TestLayout < TestInteractive
       ['--list-border=inline', 'inline border is only supported'],
       ['--input-border=inline', 'inline border is only supported'],
       ['--preview-window=border-inline --preview :', 'invalid preview window option: border-inline'],
-      ['--header-first --header-border=inline', '--header-first is not compatible'],
-      ['--header-first --header-lines-border=inline --header-lines=1', '--header-first is not compatible'],
       ['--header-border=inline --header-lines-border=sharp --header-lines=1',
        '--header-border=inline requires --header-lines-border to be inline or unset']
     ].each do |args, expected|