diff --git a/src/components/generator/DataInput.tsx b/src/components/generator/DataInput.tsx
index fd1b3a9..9a978de 100644
--- a/src/components/generator/DataInput.tsx
+++ b/src/components/generator/DataInput.tsx
@@ -69,9 +69,9 @@ const DataInput: React.FC<DataInputProps> = ({
   };
 
   const addManualRow = () => {
-    const base = selectedType === 'map'
-      ? { label: '', lat: '', lng: '', value: '' }
-      : { label: '', value: '', secondaryValue: '' };
+    const base: ManualInputRow = selectedType === 'map'
+      ? { id: crypto.randomUUID(), label: '', lat: '', lng: '', value: '' }
+      : { id: crypto.randomUUID(), label: '', value: '', secondaryValue: '' };
 
     onManualRowsChange([...manualRows, base]);
   };
@@ -263,7 +263,7 @@ const DataInput: React.FC<DataInputProps> = ({
               </thead>
               <tbody>
                 {manualRows.map((row, index) => (
-                  <tr key={index} className="border-b border-gray-100 dark:border-[#1F2937]">
+                  <tr key={row.id} className="border-b border-gray-100 dark:border-[#1F2937]">
                     <td className="py-2 pr-2">
                       <input
                         value={row.label}
@@ -358,10 +358,10 @@ const DataInput: React.FC<DataInputProps> = ({
 
 function getDefaultManualRows(selectedType: string): ManualInputRow[] {
   if (selectedType === 'map') {
-    return [{ label: '', lat: '', lng: '', value: '' }];
+    return [{ id: crypto.randomUUID(), label: '', lat: '', lng: '', value: '' }];
   }
 
-  return [{ label: '', value: '', secondaryValue: '' }];
+  return [{ id: crypto.randomUUID(), label: '', value: '', secondaryValue: '' }];
 }
 
 export default DataInput;
diff --git a/src/components/generator/previews/D3Preview.tsx b/src/components/generator/previews/D3Preview.tsx
index 33b93ae..2805ed7 100644
--- a/src/components/generator/previews/D3Preview.tsx
+++ b/src/components/generator/previews/D3Preview.tsx
@@ -294,6 +294,12 @@ const D3Preview: React.FC<D3PreviewProps> = ({
       const script = document.createElement('script');
       script.src = 'https://d3js.org/d3.v7.min.js';
       
+      script.onerror = () => {
+        if (containerRef.current) {
+          containerRef.current.innerHTML = '<p style="color:red;text-align:center;">Failed to load D3.js library</p>';
+        }
+      };
+
       script.onload = () => {
         // Re-run the chart creation after D3 loads
         if (containerRef.current && typeof (window as any).d3 !== 'undefined') {
@@ -539,7 +545,8 @@ const D3Preview: React.FC<D3PreviewProps> = ({
     }
 
     return () => {
-      // Clear the container on cleanup
+      // Don't remove script element — D3 stays on window and subsequent
+      // renders take the fast path without re-adding the script tag.
       if (containerRef.current) {
         containerRef.current.innerHTML = '';
       }
diff --git a/src/components/generator/previews/EChartsPreview.tsx b/src/components/generator/previews/EChartsPreview.tsx
index bbc26f3..834a1d2 100644
--- a/src/components/generator/previews/EChartsPreview.tsx
+++ b/src/components/generator/previews/EChartsPreview.tsx
@@ -77,6 +77,12 @@ const EChartsPreview: React.FC<EChartsPreviewProps> = ({
     const script = document.createElement('script');
     script.src = 'https://cdn.jsdelivr.net/npm/echarts@5.4.3/dist/echarts.min.js';
     
+    script.onerror = () => {
+      if (containerRef.current) {
+        containerRef.current.innerHTML = '<p style="color:red;text-align:center;">Failed to load ECharts library</p>';
+      }
+    };
+
     script.onload = () => {
       if (typeof (window as any).echarts !== 'undefined') {
         const echarts = (window as any).echarts;
diff --git a/src/components/generator/previews/HighchartsPreview.tsx b/src/components/generator/previews/HighchartsPreview.tsx
index e1d163a..7dc64a9 100644
--- a/src/components/generator/previews/HighchartsPreview.tsx
+++ b/src/components/generator/previews/HighchartsPreview.tsx
@@ -77,6 +77,12 @@ const HighchartsPreview: React.FC<HighchartsPreviewProps> = ({
     const script = document.createElement('script');
     script.src = 'https://code.highcharts.com/highcharts.js';
     
+    script.onerror = () => {
+      if (containerRef.current) {
+        containerRef.current.innerHTML = '<p style="color:red;text-align:center;">Failed to load Highcharts library</p>';
+      }
+    };
+
     script.onload = () => {
       if (typeof (window as any).Highcharts !== 'undefined') {
         const Highcharts = (window as any).Highcharts;
diff --git a/src/components/generator/previews/LeafletPreview.tsx b/src/components/generator/previews/LeafletPreview.tsx
index a531a6e..cf23170 100644
--- a/src/components/generator/previews/LeafletPreview.tsx
+++ b/src/components/generator/previews/LeafletPreview.tsx
@@ -139,6 +139,12 @@ const LeafletPreview: React.FC<LeafletPreviewProps> = ({
     link.rel = 'stylesheet';
     link.href = 'https://unpkg.com/leaflet@1.9.4/dist/leaflet.css';
     
+    script.onerror = () => {
+      if (containerRef.current) {
+        containerRef.current.innerHTML = '<p style="color:red;text-align:center;">Failed to load Leaflet library</p>';
+      }
+    };
+
     script.onload = () => {
       if (typeof (window as any).L !== 'undefined') {
         const L = (window as any).L;
diff --git a/src/components/generator/previews/OpenLayersPreview.tsx b/src/components/generator/previews/OpenLayersPreview.tsx
index 10d97b7..d0f7514 100644
--- a/src/components/generator/previews/OpenLayersPreview.tsx
+++ b/src/components/generator/previews/OpenLayersPreview.tsx
@@ -209,6 +209,12 @@ const OpenLayersPreview: React.FC<OpenLayersPreviewProps> = ({
       link.rel = 'stylesheet';
       link.href = 'https://cdn.jsdelivr.net/npm/ol@7.4.0/ol.css';
       
+      script.onerror = () => {
+        if (containerRef.current) {
+          containerRef.current.innerHTML = '<p style="color:red;text-align:center;">Failed to load OpenLayers library</p>';
+        }
+      };
+
       script.onload = () => {
         // Re-run the map creation after OpenLayers loads
         if (containerRef.current && typeof (window as any).ol !== 'undefined') {
@@ -286,7 +292,8 @@ const OpenLayersPreview: React.FC<OpenLayersPreviewProps> = ({
     }
 
     return () => {
-      // Clear the container on cleanup
+      // Don't remove script/link elements — OpenLayers stays on window and
+      // subsequent renders take the fast path without re-adding the CSS link.
       if (containerRef.current) {
         containerRef.current.innerHTML = '';
       }
diff --git a/src/pages/Generator.tsx b/src/pages/Generator.tsx
index b8e2cea..80bb6b8 100644
--- a/src/pages/Generator.tsx
+++ b/src/pages/Generator.tsx
@@ -46,10 +46,10 @@ const STATUS_TIMEOUT_MS = 2500;
 
 const getDefaultManualRows = (selectedType: string): ManualInputRow[] => {
   if (selectedType === 'map') {
-    return [{ label: '', lat: '', lng: '', value: '' }];
+    return [{ id: crypto.randomUUID(), label: '', lat: '', lng: '', value: '' }];
   }
 
-  return [{ label: '', value: '', secondaryValue: '' }];
+  return [{ id: crypto.randomUUID(), label: '', value: '', secondaryValue: '' }];
 };
 
 const toNumber = (value: string | number | undefined): number | null => {
@@ -109,6 +109,10 @@ const normalizeMapRows = (rows: TabularRow[]): GeoPoint[] => {
         return null;
       }
 
+      if (lat < -90 || lat > 90 || lng < -180 || lng > 180) {
+        return null;
+      }
+
       return {
         lat,
         lng,
diff --git a/src/types/data.ts b/src/types/data.ts
index 95424d6..555e27a 100644
--- a/src/types/data.ts
+++ b/src/types/data.ts
@@ -33,6 +33,7 @@ export interface GeoPoint {
 }
 
 export interface ManualInputRow {
+  id: string;
   label: string;
   value: string;
   secondaryValue?: string;