feat(rules): seed the rules dialog even when it is open

The dialog is non-modal and single-instance, so a second Create tagging
rule reaches one that is already up. Seeding it beats dropping the
request, which would read as a broken menu item.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

2 files changed, 13 insertions, 3 deletions

diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 14e4202..f9c9c65 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -1322,18 +1322,23 @@ void MainWindow::onDatabaseStatsReady(const DatabaseStats &stats,
                  number(stats.tags)));
 }
 
-void MainWindow::showTagRulesDialog()
+void MainWindow::showTagRulesDialog(const TagRule &seed)
 {
     // One dialog. A second would edit a stale copy and the last Save would
     // silently win, which is the lost-edit case the atomic write cannot help
     // with because both writers are this process.
     if (m_tagRulesDialog) {
+        // Seeded into the dialog already up rather than dropped: the menu item
+        // must do something visible, and a second dialog would edit a stale
+        // copy whose Save would silently win.
+        if (!seed.query.isEmpty())
+            m_tagRulesDialog->seedRule(seed);
         m_tagRulesDialog->raise();
         m_tagRulesDialog->activateWindow();
         return;
     }
 
-    auto *dialog = new TagRulesDialog(this);
+    auto *dialog = new TagRulesDialog(seed, this);
     dialog->setAttribute(Qt::WA_DeleteOnClose);
 
     m_tagRulesDialog = dialog;
diff --git a/src/mainwindow.h b/src/mainwindow.h
index 6e8501a..a68fcd9 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -34,6 +34,9 @@
 // Included rather than forward-declared: SyncPhaseTracker is held by value, so
 // its size must be known here. MailSync itself stays a forward declaration.
 #include "mailsync.h"
+// Complete type, not a forward declaration: showTagRulesDialog() defaults its
+// seed to TagRule().
+#include "tagrules.h"
 #include "syncmonitor.h"
 #include "tagcolors.h"
 #include "types.h"
@@ -376,7 +379,9 @@ private slots:
     void onRulePreviewRequested(const QString &query);
 
     /// Opens the auto-tagging rules editor, or raises the one already open.
-    void showTagRulesDialog();
+    /// `seed` is an optional rule to open on, used by Create tagging rule on a
+    /// saved query. A default-constructed TagRule (empty query) means none.
+    void showTagRulesDialog(const TagRule &seed = TagRule());
 
     /// Message counts for the rules dialog's queries, in the order it asked
     /// for them. Does nothing if the dialog has since closed, or if a newer