Let the column and workspace tags take a row for each line they hold

A header is a Text like a pane's tag, so a newline typed or pasted into it
should show rather than hide the lines after the first; the panes below move
down to make room, as they do for a taller pane tag.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 15 insertions, 9 deletions

diff --git a/src/mouse.zig b/src/mouse.zig
index 33646090..4b624dca 100644
--- a/src/mouse.zig
+++ b/src/mouse.zig
@@ -299,12 +299,15 @@ pub fn handleMouse(p: *Pardes, m: Mouse) void {
             return;
         };
         const x = if (p.header_column) |c| p.col_x[c] + TAG_TEXT_INSET else 0;
-        const bar = modal.lineSlice(edit.flatSurface(p, t) catch return, 0);
-        const at = @min(bar.len, panes.File.rawAtDisplay(bar, (tagColumn(p, if (p.header_column != null) .column else .workspace, p.header_column orelse 0, p.pointer_tag_hit, p.header_drag, 0) orelse (mcol -| x)) + p.header_scroll));
+        const text = edit.flatSurface(p, t) catch return;
+        const top = if (p.header_column != null) p.topBarHeight() else 0;
+        const line: u16 = @intCast(@min(mrow -| top, modal.lineCount(text) -| 1, (if (p.header_column != null) p.columnBarHeight() else p.topBarHeight()) -| 1));
+        const bar = modal.lineSlice(text, line);
+        const at = @min(bar.len, panes.File.rawAtDisplay(bar, (tagColumn(p, if (p.header_column != null) .column else .workspace, p.header_column orelse 0, p.pointer_tag_hit, p.header_drag, line) orelse (mcol -| x)) + p.header_scroll));
         // the anchor stays where the press put it
-        t.cur_row = 0;
+        t.cur_row = line;
         t.cur_col = @intCast(at);
-        t.vsel.active = t.vsel.col != t.cur_col;
+        t.vsel.active = t.vsel.row != t.cur_row or t.vsel.col != t.cur_col;
         if (m.kind == .release) p.header_drag = false;
         return;
     }
@@ -330,19 +333,22 @@ pub fn handleMouse(p: *Pardes, m: Mouse) void {
         }
         const t = if (column) |c| &p.col_tags[c] else &p.global_tag;
         const focused = p.header_focus and p.header_column == column;
-        const bar = modal.lineSlice(edit.flatSurface(p, t) catch return, 0);
+        const text = edit.flatSurface(p, t) catch return;
+        const line: u16 = @intCast(mrow - if (column != null) p.topBarHeight() else 0);
+        if (line > 0 and line >= modal.lineCount(text)) return;
+        const bar = modal.lineSlice(text, line);
         const scroll = if (focused) p.header_scroll else 0;
-        const at = @min(bar.len, panes.File.rawAtDisplay(bar, (tagColumn(p, if (column != null) .column else .workspace, column orelse 0, p.pointer_tag_hit, p.header_drag, 0) orelse (mcol -| x)) + scroll));
+        const at = @min(bar.len, panes.File.rawAtDisplay(bar, (tagColumn(p, if (column != null) .column else .workspace, column orelse 0, p.pointer_tag_hit, p.header_drag, line) orelse (mcol -| x)) + scroll));
         if (m.button == config.select_button) {
             // A clicked header is typed straight into, as a clicked tag is.
             if (!focused) p.enterHeader(column);
             t.mode = .insert;
-            t.cur_row = 0;
+            t.cur_row = line;
             t.cur_col = @intCast(at);
-            t.vsel = .{ .active = false, .row = 0, .col = @intCast(at) };
+            t.vsel = .{ .active = false, .row = line, .col = @intCast(at) };
             p.header_drag = true;
         } else {
-            const span = if (focused) Pardes.headerSelection(t, bar) else null;
+            const span = if (focused) Pardes.headerSelection(t, text, line) else null;
             const selected = if (span) |sp|
                 (if (at >= sp.lo and at < sp.hi) bar[sp.lo..sp.hi] else wordAtCol(bar, at))
             else