diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 2530d25..6e58be9 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -182,6 +182,7 @@ export default function App() {
         custom_colors: {
           border: data.border_color,
           border_style: data.border_style,
+          border_width: data.border_width,
           background: data.background_color,
           text_color: data.text_color,
           text_position: data.text_position,
@@ -198,6 +199,7 @@ export default function App() {
 
   const handleUpdateGroupRect = useCallback((data: GroupRectFormData) => {
     if (!editingGroupRectId) return
+    snapshotHistory()
     const existing = nodes.find((n) => n.id === editingGroupRectId)
     updateNode(editingGroupRectId, {
       label: data.label,
@@ -205,6 +207,7 @@ export default function App() {
         ...existing?.data.custom_colors,
         border: data.border_color,
         border_style: data.border_style,
+        border_width: data.border_width,
         background: data.background_color,
         text_color: data.text_color,
         text_position: data.text_position,
@@ -214,7 +217,7 @@ export default function App() {
     })
     setNodeZIndex(editingGroupRectId, data.z_order - 10)
     setEditingGroupRectId(null)
-  }, [editingGroupRectId, nodes, updateNode, setNodeZIndex, setEditingGroupRectId])
+  }, [editingGroupRectId, nodes, updateNode, setNodeZIndex, setEditingGroupRectId, snapshotHistory])
 
   const handleDeleteGroupRect = useCallback(() => {
     if (!editingGroupRectId) return
@@ -436,7 +439,7 @@ export default function App() {
           open={addGroupRectOpen}
           onClose={() => setAddGroupRectOpen(false)}
           onSubmit={handleAddGroupRect}
-          title="Add Rectangle"
+          title="Add Zone"
         />
 
         {/* key forces re-mount when editing a different rect */}
@@ -457,11 +460,12 @@ export default function App() {
               text_position: rc.text_position ?? 'top-left',
               border_color: rc.border ?? '#00d4ff',
               border_style: rc.border_style ?? 'solid',
+              border_width: rc.border_width ?? 2,
               background_color: rc.background ?? '#00d4ff0d',
               z_order: rc.z_order ?? 1,
             }
           })()}
-          title="Edit Rectangle"
+          title="Edit Zone"
         />
 
         {/* key forces re-mount on open so useState captures current theme as original */}
diff --git a/frontend/src/components/canvas/nodes/GroupRectNode.tsx b/frontend/src/components/canvas/nodes/GroupRectNode.tsx
index bd6bfe9..45f2879 100644
--- a/frontend/src/components/canvas/nodes/GroupRectNode.tsx
+++ b/frontend/src/components/canvas/nodes/GroupRectNode.tsx
@@ -32,6 +32,7 @@ export function GroupRectNode({ id, data, selected }: NodeProps<Node<NodeData>>)
   const rc = data.custom_colors ?? {}
   const borderColor = rc.border ?? '#00d4ff'
   const borderStyle = rc.border_style ?? 'solid'
+  const borderWidth = rc.border_width ?? 2
   const backgroundColor = rc.background ?? 'rgba(0,212,255,0.05)'
   const textColor = rc.text_color ?? '#e6edf3'
   const fontFamily = FONT_FAMILIES[rc.font ?? 'inter'] ?? FONT_FAMILIES.inter
@@ -62,7 +63,7 @@ export function GroupRectNode({ id, data, selected }: NodeProps<Node<NodeData>>)
           justifyContent: posStyle.justifyContent,
           padding: 12,
           background: backgroundColor,
-          border: `${selected ? 2 : 1}px ${selected ? 'solid' : borderStyle} ${selected ? '#00d4ff' : borderColor}`,
+          border: `${selected ? borderWidth + 1 : borderWidth}px ${selected ? 'solid' : borderStyle} ${selected ? '#00d4ff' : borderColor}`,
           borderRadius: 10,
           fontFamily,
           color: textColor,
diff --git a/frontend/src/components/modals/GroupRectModal.tsx b/frontend/src/components/modals/GroupRectModal.tsx
index ad1b490..b437b67 100644
--- a/frontend/src/components/modals/GroupRectModal.tsx
+++ b/frontend/src/components/modals/GroupRectModal.tsx
@@ -15,6 +15,7 @@ export interface GroupRectFormData {
   text_position: TextPosition
   border_color: string
   border_style: BorderStyle
+  border_width: number
   background_color: string
   z_order: number
 }
@@ -27,6 +28,14 @@ const BORDER_STYLES: { value: BorderStyle; label: string; preview: string }[] =
   { value: 'none',   label: 'None',   preview: '   ' },
 ]
 
+const BORDER_WIDTHS: { value: number; label: string }[] = [
+  { value: 1, label: '1px' },
+  { value: 2, label: '2px' },
+  { value: 3, label: '3px' },
+  { value: 4, label: '4px' },
+  { value: 5, label: '5px' },
+]
+
 const DEFAULT_FORM: GroupRectFormData = {
   label: '',
   font: 'inter',
@@ -34,6 +43,7 @@ const DEFAULT_FORM: GroupRectFormData = {
   text_position: 'top-left',
   border_color: '#00d4ff',
   border_style: 'solid',
+  border_width: 2,
   background_color: '#00d4ff0d',
   z_order: 1,
 }
@@ -65,7 +75,7 @@ interface GroupRectModalProps {
   title?: string
 }
 
-export function GroupRectModal({ open, onClose, onSubmit, onDelete, initial, title = 'Add Rectangle' }: GroupRectModalProps) {
+export function GroupRectModal({ open, onClose, onSubmit, onDelete, initial, title = 'Add Zone' }: GroupRectModalProps) {
   const [form, setForm] = useState<GroupRectFormData>({ ...DEFAULT_FORM, ...initial })
 
   const set = <K extends keyof GroupRectFormData>(key: K, value: GroupRectFormData[K]) =>
@@ -196,6 +206,31 @@ export function GroupRectModal({ open, onClose, onSubmit, onDelete, initial, tit
             </div>
           </div>
 
+          {/* Border width */}
+          <div className="flex flex-col gap-1.5">
+            <Label className="text-xs text-muted-foreground">Border Width</Label>
+            <div className="grid grid-cols-5 gap-1">
+              {BORDER_WIDTHS.map(({ value, label }) => {
+                const isSelected = form.border_width === value
+                return (
+                  <button
+                    key={value}
+                    type="button"
+                    onClick={() => set('border_width', value)}
+                    className="flex items-center justify-center h-8 rounded text-xs transition-colors"
+                    style={{
+                      background: isSelected ? '#00d4ff22' : '#21262d',
+                      border: `1px solid ${isSelected ? '#00d4ff88' : '#30363d'}`,
+                      color: isSelected ? '#00d4ff' : '#8b949e',
+                    }}
+                  >
+                    {label}
+                  </button>
+                )
+              })}
+            </div>
+          </div>
+
           {/* Z-order */}
           <div className="flex flex-col gap-1.5">
             <Label className="text-xs text-muted-foreground">Z-Order (1 = furthest back)</Label>
@@ -230,7 +265,7 @@ export function GroupRectModal({ open, onClose, onSubmit, onDelete, initial, tit
                 Cancel
               </Button>
               <Button type="submit" size="sm" className="bg-[#00d4ff] text-[#0d1117] hover:bg-[#00d4ff]/90">
-                {title === 'Add Rectangle' ? 'Add' : 'Save'}
+                {title === 'Add Zone' ? 'Add' : 'Save'}
               </Button>
             </div>
           </div>
diff --git a/frontend/src/components/modals/__tests__/GroupRectModal.test.tsx b/frontend/src/components/modals/__tests__/GroupRectModal.test.tsx
index 896b752..40f1528 100644
--- a/frontend/src/components/modals/__tests__/GroupRectModal.test.tsx
+++ b/frontend/src/components/modals/__tests__/GroupRectModal.test.tsx
@@ -13,14 +13,15 @@ describe('GroupRectModal', () => {
   it('renders form fields when open', () => {
     render(<GroupRectModal open onClose={vi.fn()} onSubmit={vi.fn()} />)
     expect(screen.getByPlaceholderText('Zone name…')).toBeDefined()
-    expect(screen.getByText('Add Rectangle')).toBeDefined()
+    expect(screen.getByText('Add Zone')).toBeDefined()
     expect(screen.getByText('Text Position')).toBeDefined()
+    expect(screen.getByText('Border Width')).toBeDefined()
     expect(screen.getByText('Z-Order (1 = furthest back)')).toBeDefined()
   })
 
-  it('renders Edit Rectangle title when provided', () => {
-    render(<GroupRectModal open onClose={vi.fn()} onSubmit={vi.fn()} title="Edit Rectangle" />)
-    expect(screen.getByText('Edit Rectangle')).toBeDefined()
+  it('renders Edit Zone title when provided', () => {
+    render(<GroupRectModal open onClose={vi.fn()} onSubmit={vi.fn()} title="Edit Zone" />)
+    expect(screen.getByText('Edit Zone')).toBeDefined()
   })
 
   it('calls onSubmit with form data on submit', () => {
@@ -123,6 +124,46 @@ describe('GroupRectModal', () => {
     expect(submitted.border_style).toBe('dotted')
   })
 
+  it('renders Border Width section with 5 options', () => {
+    render(<GroupRectModal open onClose={vi.fn()} onSubmit={vi.fn()} />)
+    expect(screen.getByText('Border Width')).toBeDefined()
+    expect(screen.getByText('1px')).toBeDefined()
+    expect(screen.getByText('3px')).toBeDefined()
+    expect(screen.getByText('5px')).toBeDefined()
+  })
+
+  it('defaults border_width to 2', () => {
+    const onSubmit = vi.fn()
+    render(<GroupRectModal open onClose={vi.fn()} onSubmit={onSubmit} />)
+    fireEvent.click(screen.getByText('Add'))
+    const submitted = onSubmit.mock.calls[0][0] as GroupRectFormData
+    expect(submitted.border_width).toBe(2)
+  })
+
+  it('selects border width on click', () => {
+    const onSubmit = vi.fn()
+    render(<GroupRectModal open onClose={vi.fn()} onSubmit={onSubmit} />)
+    fireEvent.click(screen.getByText('4px'))
+    fireEvent.click(screen.getByText('Add'))
+    const submitted = onSubmit.mock.calls[0][0] as GroupRectFormData
+    expect(submitted.border_width).toBe(4)
+  })
+
+  it('pre-fills border_width from initial prop', () => {
+    const onSubmit = vi.fn()
+    render(
+      <GroupRectModal
+        open
+        onClose={vi.fn()}
+        onSubmit={onSubmit}
+        initial={{ border_width: 5 }}
+      />
+    )
+    fireEvent.click(screen.getByText('Add'))
+    const submitted = onSubmit.mock.calls[0][0] as GroupRectFormData
+    expect(submitted.border_width).toBe(5)
+  })
+
   it('toggles border style — clicking selected style deselects back to solid', () => {
     const onSubmit = vi.fn()
     render(<GroupRectModal open onClose={vi.fn()} onSubmit={onSubmit} />)
diff --git a/frontend/src/components/panels/Sidebar.tsx b/frontend/src/components/panels/Sidebar.tsx
index 90690c3..3105bdb 100644
--- a/frontend/src/components/panels/Sidebar.tsx
+++ b/frontend/src/components/panels/Sidebar.tsx
@@ -124,7 +124,7 @@ export function Sidebar({ onAddNode, onAddGroupRect, onScan, onSave, onNodeAppro
       {/* Actions */}
       <div className="flex flex-col gap-0.5 p-2 border-t border-border">
         <SidebarItem icon={Plus} label="Add Node" collapsed={collapsed} onClick={onAddNode} />
-        <SidebarItem icon={Square} label="Add Rectangle" collapsed={collapsed} onClick={onAddGroupRect} />
+        <SidebarItem icon={Square} label="Add Zone" collapsed={collapsed} onClick={onAddGroupRect} />
         {!STANDALONE && <SidebarItem icon={ScanLine} label="Scan Network" collapsed={collapsed} onClick={handleScan} />}
         <SidebarItem
           icon={hideIp ? EyeOff : Eye}
@@ -303,7 +303,7 @@ function HiddenDevicesPanel() {
     }
   }, [])
 
-  useState(() => { load() })
+  useEffect(() => { load() }, [load])
 
   const handleIgnore = async (id: string) => {
     try {