fix(kpa): a settings save must not flick the KPA500's power switch — and the maps stay under the menus

startAmps tore down and rebuilt every amplifier client on any settings
save, and closing a COM port makes the Windows driver drop DTR/RTS. On a
KPA500 those lines ARE the power switch — so 'save' meant 'amplifier off
twenty seconds later', exactly F1TPL's report, and the fix that held the
lines while OPEN couldn't survive a close. An amplifier whose config is
unchanged now keeps its running client across saves; the others still
rebuild.

Also: isolate on the FT Map panel — Leaflet's z-1000 panes were painting
over the menu bar and the Preferences dialog, as the grid map's own
comment warned.

app.go

@@ -18677,19 +18677,51 @@ func (a *App) startAmps() {
 	old := a.ampInsts
 	a.ampInsts = map[string]*ampInst{}
 	a.ampsMu.Unlock()
-	for _, inst := range old {
+	a.pgxl, a.spe, a.acom = nil, nil, nil
+	list, err := a.GetAmplifiers()
+	if err != nil {
+		for _, inst := range old {
+			go inst.stopAll()
+		}
+		return
+	}
+	// An amplifier whose configuration did not change keeps its RUNNING client
+	// across a settings save. Rebuilding closes the serial port, and closing a
+	// COM port makes the Windows driver drop DTR/RTS — which on a KPA500 is the
+	// POWER SWITCH: every save of any Settings page was switching the amplifier
+	// off (F1TPL's report). Reuse also spares the other amps a reconnect blink.
+	reused := map[string]bool{}
+	for _, c := range list {
+		if !c.Enabled {
+			continue
+		}
+		if o, ok := old[c.ID]; ok && o.cfg == c {
+			reused[c.ID] = true
+			if o.pgxl != nil && a.pgxl == nil {
+				a.pgxl = o.pgxl
+			}
+			if o.spe != nil && a.spe == nil {
+				a.spe = o.spe
+			}
+			if o.acom != nil && a.acom == nil {
+				a.acom = o.acom
+			}
+			a.ampsMu.Lock()
+			a.ampInsts[c.ID] = o
+			a.ampsMu.Unlock()
+		}
+	}
+	for id, inst := range old {
+		if reused[id] {
+			continue
+		}
 		// Stop() can block up to the dial timeout waiting for an in-progress
 		// connect; tear down in the background so saving Settings (this runs on
 		// the Wails RPC goroutine) doesn't freeze the UI.
 		go inst.stopAll()
 	}
-	a.pgxl, a.spe, a.acom = nil, nil, nil
-	list, err := a.GetAmplifiers()
-	if err != nil {
-		return
-	}
 	for _, c := range list {
-		if !c.Enabled {
+		if !c.Enabled || reused[c.ID] {
 			continue
 		}
 		isPGXL := c.Type == "" || c.Type == "pgxl"

changelog.json

@@ -5,12 +5,16 @@
     "en": [
       "QSL Manager: Club Log confirmations — downloads your log matches (getmatches API) and stamps two new columns, ClubLog match status and match date, available everywhere: table columns, filters, bulk edit and the QSO editor.",
       "Super Check Partial: option to merge Club Log’s weekly call list (~180k calls heard on the air in the last 3 years) with MASTER.SCP.",
-      "Fixed: opening the app could silently stop at startup (settings showing as default, “db not initialized”) when a database migration targeted a table that database no longer holds — migrations now skip what does not apply, and a startup failure is written to the log."
+      "Fixed: opening the app could silently stop at startup (settings showing as default, “db not initialized”) when a database migration targeted a table that database no longer holds — migrations now skip what does not apply, and a startup failure is written to the log.",
+      "FT Map / Grid squares: the map no longer floats above the menus and the Preferences dialog.",
+      "KPA500: saving ANY settings page no longer power-cycles the amplifier. A save rebuilt every amplifier connection, and closing the COM port drops DTR/RTS — the KPA500’s power switch. An unchanged amplifier now keeps its running connection across saves."
     ],
     "fr": [
       "QSL Manager : confirmations Club Log — télécharge vos matches de log (API getmatches) et remplit deux nouvelles colonnes, statut et date de match ClubLog, disponibles partout : colonnes du tableau, filtres, édition groupée et éditeur de QSO.",
       "Super Check Partial : option pour fusionner la liste hebdomadaire de Club Log (~180k indicatifs entendus sur l’air ces 3 dernières années) avec MASTER.SCP.",
-      "Corrigé : l’application pouvait se figer silencieusement au démarrage (réglages par défaut, « db not initialized ») quand une migration visait une table absente de cette base — les migrations ignorent désormais ce qui ne s’applique pas, et un échec de démarrage est écrit dans le log."
+      "Corrigé : l’application pouvait se figer silencieusement au démarrage (réglages par défaut, « db not initialized ») quand une migration visait une table absente de cette base — les migrations ignorent désormais ce qui ne s’applique pas, et un échec de démarrage est écrit dans le log.",
+      "FT Map / Grid squares : la carte ne passe plus au-dessus des menus et de la fenêtre Préférences.",
+      "KPA500 : sauvegarder n’importe quelle page des réglages n’éteint plus l’ampli. Une sauvegarde reconstruisait chaque connexion d’ampli, et fermer le port COM relâche DTR/RTS — l’interrupteur d’alimentation du KPA500. Un ampli inchangé garde désormais sa connexion à travers les sauvegardes."
     ]
   },
   {

frontend/src/components/FTMapPanel.tsx

@@ -119,7 +119,10 @@ export function FTMapPanel({ decodes, myGrid }: { decodes: FTMapDecode[]; myGrid
 
   const bands = [...new Set(decodes.map((d) => (d.band ?? '').toLowerCase()).filter(Boolean))];
   return (
-    <div className="relative h-full w-full min-h-0">
+    // isolate: Leaflet stacks its panes and controls up to z-index 1000, which
+    // beat the app menus and the Settings dialog. A stacking context of our own
+    // keeps all of it inside this panel.
+    <div className="relative isolate z-0 h-full w-full min-h-0">
       <div ref={divRef} className="absolute inset-0 rounded-lg overflow-hidden" />
       {/* Basemap picker, MainMap's own vocabulary. */}
       <div className="absolute top-2 left-12 z-[1000] flex gap-1 rounded-md bg-background/85 backdrop-blur px-1 py-1 border border-border">