A column can be empty, as acme's can; new panes go where acme's makenewwindow puts them

Newcol makes an empty column; closing a column's last pane leaves it empty with
the keyboard on its tag; Delcol and Joincol alone take a column away; the
session's last pane closing quits. The +New stand-in and replaceStillborn /
stillborn_joiner are gone. Every new pane goes through exec.placeNew, which
follows acme's makenewwindow (active column, empty column whole, blank space,
halving the biggest) or, with Placement pardes, the old rules. ColumnTags is
gone: column tags are always shown. A grip drag shows acme's box cursor.

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

1 files changed, 9 insertions, 2 deletions

diff --git a/src/mouse.zig b/src/mouse.zig
index 22eb3270..5f0a6c4b 100644
--- a/src/mouse.zig
+++ b/src/mouse.zig
@@ -337,6 +337,9 @@ pub fn handleMouse(p: *Pardes, m: Mouse) void {
                 wordAtCol(bar, at);
             const word = p.scratch.allocator().dupe(u8, selected) catch return;
             tagline.exitHeader(p);
+            // A column tag's command acts on that column, empty or not.
+            p.exec_column = column;
+            defer p.exec_column = null;
             if (word.len > 0) {
                 if (m.button == config.exec_button) {
                     const named = std.meta.stringToEnum(Builtin, word);
@@ -450,6 +453,7 @@ pub fn handleMouse(p: *Pardes, m: Mouse) void {
                     const on_tag = mrow >= tag_y and mrow < tag_y + pane.tag_rows;
                     if (on_tag and mcol < r.x + TAG_TEXT_INSET) return;
                     p.active = id;
+                    p.noteTyped(); // acme's button 1 sets activecol (acme.c:659)
                     pane.closePrompt();
                     const pointed = edit.pointerTextSelection(p, id, mcol, mrow, m.body_hit, p.pointer_tag_hit) orelse return;
                     pane.clearPointerSelection(sel_slot);
@@ -775,12 +779,15 @@ fn dragRelease(p: *Pardes, button: Mouse.Button) void {
             layout.applyRowSplit(p, d.col, d.top_idx, d.cur_y),
         .column_move => |d| if (layout.columnBySerial(p, d.serial)) |column| switch (layout.columnDrop(p, column, d.cur_x, d.grab)) {
             .stay => {},
-            .reorder => |target| layout.reorderColumn(p, column, target),
+            .reorder => |target| {
+                layout.reorderColumn(p, column, target);
+                p.setActiveColumn(target); // a grip drag sets activecol (acme.c:640)
+            },
             .edge => |x| layout.setColumnPairWidth(p, column - 1, x - p.col_x[column - 1]),
         },
         .move => |d| {
             layout.movePane(p, d.id, d.cur_x, d.cur_y);
-            if (p.panes[d.id]) |mp| p.stillborn_joiner = mp.serial;
+            if (layout.findPane(p, d.id)) |f| p.setActiveColumn(f.col);
             // a file moved into the left column evicts a lone unused shell
             if (p.panes[d.id]) |mt| if (mt.file != null) {
                 if (layout.findPane(p, d.id)) |f| if (f.col == 0)