From 1904428fbba5f59e97e768084cf044073220b008 Mon Sep 17 00:00:00 2001
From: Paul Trowbridge <paul@hptrow.me>
Date: Thu, 17 Sep 2026 01:37:33 -0400
Subject: [PATCH] Say that a clone's selection is the source, not the
 destination

The slice filters the rows being copied, so cloning prior year forward means
selecting last December and shifting it, not selecting the December you want
to fill. Selecting the destination matches nothing -- prior year's rows are
labelled with prior year's periods, so a 2027 slice and a 2026 segment share
no rows -- and it fails silently, as zero rows cloned.

Nothing in the form said which way round it was, and "copy from <segment>"
reads like the selection is the target. It now says the selection is what
gets copied, and the segment narrows it rather than replacing it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 ui/src/components/OperationPanel.jsx | 29 +++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/ui/src/components/OperationPanel.jsx b/ui/src/components/OperationPanel.jsx
index ee43bd9..ba622da 100644
--- a/ui/src/components/OperationPanel.jsx
+++ b/ui/src/components/OperationPanel.jsx
@@ -786,17 +786,18 @@ export default function OperationPanel({
                        slices={slices} lookupDerivedCols={lookupDerivedCols} dimMembers={dimMembers} versionId={versionId}
                        extra={
                          <div className="flex flex-col gap-2">
-                           {/* Where the mix comes from. Left on the adjustable rows,
-                               clone behaves as it always did. Naming a segment reads
-                               from that entry instead -- including the reference ones
-                               operations are normally kept away from, which is the
-                               point: a period with no baseline borrows a shape from
-                               prior year or plan. */}
+                           {/* The selection is the SOURCE, not the destination: pick
+                               the cells you want to copy -- last December, say -- and
+                               the shift below is what lands them in the target period.
+                               Naming a segment narrows that selection to one entry,
+                               including the reference ones operations are normally kept
+                               away from, which is the point: a period with no baseline
+                               borrows its shape from prior year or plan. */}
                            <div className="flex items-center gap-2 flex-wrap">
-                             <span className="text-gray-500 whitespace-nowrap">copy from</span>
+                             <span className="text-gray-500 whitespace-nowrap">copy rows from</span>
                              <select value={cloneFrom} onChange={e => setCloneFrom(e.target.value)}
                                      className={`${INPUT} w-auto`}>
-                               <option value="">current selection</option>
+                               <option value="">the whole selection</option>
                                {(cloneSources || []).map(s => (
                                  <option key={s.id} value={s.id}>
                                    {s.label || `${s.operation} #${s.id}`}
@@ -818,11 +819,17 @@ export default function OperationPanel({
                                  <option value="24 months" />
                                  <option value="0 days" />
                                </datalist>
-                               <span className="text-gray-400 text-[11px]">
-                                 every date column, with period dimensions re-derived
-                               </span>
                              </div>
                            )}
+                           {cloneFrom && (
+                             <p className="text-gray-500 text-[11px] leading-snug max-w-sm">
+                               The cells you have selected are what gets copied. Shifting
+                               moves every date column, and the season and month
+                               dimensions are re-derived from the calendar to match — so
+                               select the period you are copying <em>from</em>, not the
+                               one you are filling.
+                             </p>
+                           )}
 
                            <div className="flex items-center gap-2">
                              <span className="text-gray-500">scale cloned rows by</span>