improve drag

src/App.tsx

@@ -39,18 +39,27 @@ const snapToGrid = (x: number, y: number): { x: number; y: number } => ({
   y: Math.round(y / SNAP_GRID[1]) * SNAP_GRID[1],
 })
 
+const DEFAULT_NODE_STYLE: Record<string, { width: number; height: number }> = {
+  config: { width: 320, height: 320 },
+  render: { width: 384, height: 320 },
+  variable: { width: 224, height: 180 },
+  function: { width: 288, height: 260 },
+}
+
 const initialNodes: Node[] = [
   {
     id: 'config-1',
     position: { x: 50, y: 50 },
     data: { plantuml: '@startuml\nactor User\nparticipant "Render" as R\nUser -> R : config\n@enduml\n' },
     type: 'config',
+    style: DEFAULT_NODE_STYLE.config,
   },
   {
     id: 'render-1',
     position: { x: 350, y: 80 },
     data: {},
     type: 'render',
+    style: DEFAULT_NODE_STYLE.render,
   },
 ].map((n) => ({ ...n, id: n.id ?? genId() }))
 
@@ -133,11 +142,13 @@ export default function App() {
         variable: { value: '', valueType: 'string' },
         function: { body: '// args[0], args[1], ...\nreturn args[0];' },
       }
+      const nodeType = typeMap[type] ?? 'config'
       const newNode: Node = {
         id,
-        type: typeMap[type] ?? 'config',
+        type: nodeType,
         position: { x: position.x, y: position.y },
         data: dataMap[type] ?? {},
+        style: DEFAULT_NODE_STYLE[nodeType] ?? DEFAULT_NODE_STYLE.config,
       }
       setNodes((nds) => nds.concat(newNode))
       lastClickRef.current = null

src/components/graph/BaseNode.tsx

@@ -1,8 +1,48 @@
-import type { ComponentProps } from "react";
+import type { ComponentProps, ReactNode } from "react";
+import { NodeResizeControl } from "@xyflow/react";
 
 import { cn } from "@/lib/utils";
 
-export function BaseNode({ className, ...props }: ComponentProps<"div">) {
+export type BaseNodeProps = ComponentProps<"div"> & {
+  /** When true, shows a bottom-right resize handle. Requires nodeId when used inside React Flow. */
+  resizable?: boolean;
+  /** Node id for the resize control (required when resizable is true). */
+  nodeId?: string;
+  /** Connection handles (InputHandle, OutputHandle). Rendered outside the overflow layer so they stay visible. */
+  handles?: ReactNode;
+  /** When provided, node uses this size (e.g. from React Flow width/height). Enables correct resize behavior. */
+  dimensions?: { width: number; height: number };
+};
+
+export function BaseNode({
+  className,
+  style,
+  dimensions,
+  resizable,
+  nodeId,
+  handles,
+  children,
+  ...props
+}: BaseNodeProps) {
+  const hasSize =
+    dimensions &&
+    dimensions.width > 0 &&
+    dimensions.height > 0;
+  // Don't set overflow: hidden on the root — handles are positioned at left/right -10px
+  // and would be clipped. The inner content wrapper has overflow-hidden for scrolling.
+  const appliedStyle = hasSize
+    ? {
+        ...style,
+        width: dimensions.width,
+        height: dimensions.height,
+        display: "flex" as const,
+        flexDirection: "column" as const,
+        contain: "layout" as const,
+      }
+    : style
+      ? { ...style, display: "flex", flexDirection: "column" as const }
+      : undefined;
+
   return (
     <div
       className={cn(
@@ -17,9 +57,38 @@ export function BaseNode({ className, ...props }: ComponentProps<"div">) {
         "[.react-flow\\_\\_node.selected_&]:shadow-lg",
         className,
       )}
+      style={appliedStyle}
       tabIndex={0}
       {...props}
-    />
+    >
+      <div
+        className="min-h-0 flex-1 flex flex-col overflow-hidden"
+        style={{ contain: "layout" }}
+      >
+        {children}
+      </div>
+      {resizable && nodeId && (
+        <NodeResizeControl
+          nodeId={nodeId}
+          position="bottom-right"
+          minWidth={120}
+          minHeight={80}
+          className={cn(
+            "!border-0 !bg-transparent !rounded-none !p-0",
+            "absolute bottom-0 right-0 w-8 h-8 cursor-se-resize select-none",
+            "nodrag nopan touch-none",
+          )}
+          style={{ margin: 0, touchAction: "none", userSelect: "none" }}
+        >
+          <span
+            className="absolute bottom-0 right-0 w-8 h-8 rounded-br border-l border-t border-border/30 hover:border-border/50"
+            title="Drag corner to resize"
+            aria-label="Resize node"
+          />
+        </NodeResizeControl>
+      )}
+      {handles}
+    </div>
   );
 }
 
@@ -35,7 +104,7 @@ export function BaseNodeHeader({
     <header
       {...props}
       className={cn(
-        "mx-0 my-0 -mb-1 flex flex-row items-center justify-between gap-2 px-3 py-2",
+        "shrink-0 mx-0 my-0 -mb-1 flex flex-row items-center justify-between gap-2 px-3 py-2",
         // Remove or modify these classes if you modify the padding in the
         // `<BaseNode />` component.
         className,
@@ -61,6 +130,53 @@ export function BaseNodeHeaderTitle({
   );
 }
 
+/**
+ * Standard node header: icon on the left, title taking the rest. Use for all node types.
+ * Inlined so it does not depend on BaseNodeHeader/BaseNodeHeaderTitle (avoids reference errors with HMR).
+ */
+export function BaseNodeHeaderRow({
+  icon,
+  title,
+  className,
+}: {
+  icon: ReactNode;
+  title: ReactNode;
+  className?: string;
+}) {
+  return (
+    <header
+      className={cn(
+        "shrink-0 mx-0 my-0 -mb-1 flex flex-row items-center justify-between gap-2 border-b px-3 py-2",
+        className,
+      )}
+    >
+      {icon}
+      <h3
+        data-slot="base-node-title"
+        className="user-select-none flex-1 font-semibold"
+      >
+        {title}
+      </h3>
+    </header>
+  );
+}
+
+/**
+ * Single-line muted text for the footer. Use for status or hints in all node types.
+ */
+export function BaseNodeFooterText({
+  className,
+  ...props
+}: ComponentProps<"div">) {
+  return (
+    <div
+      className={cn("w-full text-xs text-muted-foreground", className)}
+      data-slot="base-node-footer-text"
+      {...props}
+    />
+  );
+}
+
 export function BaseNodeContent({
   className,
   ...props
@@ -68,7 +184,7 @@ export function BaseNodeContent({
   return (
     <div
       data-slot="base-node-content"
-      className={cn("flex flex-col gap-y-2 pt-1", className)}
+      className={cn("min-h-0 flex-1 flex flex-col gap-y-2 overflow-auto pt-1", className)}
       {...props}
     />
   );
@@ -79,7 +195,7 @@ export function BaseNodeFooter({ className, ...props }: ComponentProps<"div">) {
     <div
       data-slot="base-node-footer"
       className={cn(
-        "flex flex-col items-center gap-y-2 border-t px-3 pt-2 pb-3",
+        "shrink-0 flex flex-col items-center gap-y-2 border-t px-3 pt-2 pb-3",
         className,
       )}
       {...props}

src/components/graph/ConfigNode.tsx

@@ -1,14 +1,15 @@
 import React, { memo, useCallback, useContext, useEffect, useMemo, useRef, useState } from 'react'
 import CodeMirror from '@uiw/react-codemirror'
 import FlowContext from '../../lib/flowContext'
+import { useResizeHeight } from '../../hooks/useResizeHeight'
 import { plantumlLanguage } from '../../lib/plantumlLanguage'
 import { useTheme } from '../../lib/themeContext'
 import {
     BaseNode,
     BaseNodeContent,
     BaseNodeFooter,
-    BaseNodeHeader,
-    BaseNodeHeaderTitle,
+    BaseNodeFooterText,
+    BaseNodeHeaderRow,
 } from './BaseNode'
 import { GitBranchPlus, ScrollText } from 'lucide-react'
 import {
@@ -26,9 +27,11 @@ import { InputHandle, OutputHandle } from './NodeHandles'
 type Props = {
     id: string
     data: any
+    width?: number
+    height?: number
 }
 
-export const ConfigNode = memo(function ConfigNode({ id, data }: Props) {
+export const ConfigNode = memo(function ConfigNode({ id, data, width, height }: Props) {
     const [value, setValue] = useState<string>(data?.plantuml ?? '@startuml\n\n@enduml\n')
     const { theme } = useTheme()
     const ctx = useContext(FlowContext)
@@ -114,17 +117,20 @@ export const ConfigNode = memo(function ConfigNode({ id, data }: Props) {
     )
 
     const extensions = useMemo(() => [plantumlLanguage.extension], [])
+    const [editorHeight, editorContainerRef] = useResizeHeight(180)
+
+    const dimensions =
+        width != null && height != null && width > 0 && height > 0
+            ? { width, height }
+            : undefined
 
     return (
-        <BaseNode className="w-80">
-            <BaseNodeHeader className="border-b">
-                <ScrollText className="size-4" />
-                <BaseNodeHeaderTitle>{id}.puml</BaseNodeHeaderTitle>
-            </BaseNodeHeader>
+        <BaseNode className="min-w-80 min-h-[280px]" dimensions={dimensions} resizable nodeId={id} handles={<><InputHandle id="ain" /><OutputHandle id="out" /></>}>
+            <BaseNodeHeaderRow icon={<ScrollText className="size-4" />} title={`${id}.puml`} />
 
             <BaseNodeContent>
                 {hasDependencies && (
-                    <div className="w-full">
+                    <div className="shrink-0 w-full">
                         <Menubar className="h-auto bg-none p-1 border-none shadow-none">
                             <MenubarMenu>
                                 <MenubarTrigger className="px-1.5 py-0 text-xs">
@@ -194,12 +200,12 @@ export const ConfigNode = memo(function ConfigNode({ id, data }: Props) {
                     </div>
                 )}
 
-                <div style={{ height: 180 }} className="w-full nodrag nopan overflow-hidden rounded border border-input">
+                <div ref={editorContainerRef} className="min-h-0 flex-1 w-full nodrag nopan overflow-hidden rounded border border-input">
                     <CodeMirror
                         // @ts-expect-error ref is { view, state, editor }; package ref type not in our node_modules
                         ref={editorRef}
                         value={value}
-                        height="180px"
+                        height={`${editorHeight}px`}
                         theme={theme}
                         extensions={extensions}
                         onChange={onChange}
@@ -210,11 +216,8 @@ export const ConfigNode = memo(function ConfigNode({ id, data }: Props) {
             </BaseNodeContent>
 
             <BaseNodeFooter>
-                <div className="w-full text-xs text-muted-foreground">{storedPlantuml ? `${storedPlantuml.length} chars` : 'none'}</div>
+                <BaseNodeFooterText>{storedPlantuml ? `${storedPlantuml.length} chars` : 'none'}</BaseNodeFooterText>
             </BaseNodeFooter>
-
-            <InputHandle id="ain" />
-            <OutputHandle id="out" />
         </BaseNode>
     )
 })

src/components/graph/FunctionNode.tsx

@@ -2,13 +2,14 @@ import React, { memo, useCallback, useContext, useEffect, useMemo, useRef, useSt
 import CodeMirror from '@uiw/react-codemirror'
 import { javascript } from '@codemirror/lang-javascript'
 import FlowContext from '../../lib/flowContext'
+import { useResizeHeight } from '../../hooks/useResizeHeight'
 import { useTheme } from '../../lib/themeContext'
 import {
     BaseNode,
     BaseNodeContent,
     BaseNodeFooter,
-    BaseNodeHeader,
-    BaseNodeHeaderTitle,
+    BaseNodeFooterText,
+    BaseNodeHeaderRow,
 } from './BaseNode'
 import { InputHandle, OutputHandle } from './NodeHandles'
 import { Code2 } from 'lucide-react'
@@ -16,13 +17,15 @@ import { Code2 } from 'lucide-react'
 type Props = {
     id: string
     data: { body?: string }
+    width?: number
+    height?: number
 }
 
 const DEFAULT_BODY = `// args[0], args[1], ... are the variable values (in order)
 return args[0];
 `
 
-export const FunctionNode = memo(function FunctionNode({ id, data }: Props) {
+export const FunctionNode = memo(function FunctionNode({ id, data, width, height }: Props) {
     const [value, setValue] = useState<string>(data?.body ?? DEFAULT_BODY)
     const { theme } = useTheme()
     const ctx = useContext(FlowContext)
@@ -52,22 +55,24 @@ export const FunctionNode = memo(function FunctionNode({ id, data }: Props) {
     const storedBody = ctx?.nodes?.find((n: any) => n.id === id)?.data?.body ?? ''
 
     const extensions = useMemo(() => [javascript()], [])
+    const [editorHeight, editorContainerRef] = useResizeHeight(120)
+    const dimensions =
+        width != null && height != null && width > 0 && height > 0
+            ? { width, height }
+            : undefined
 
     return (
-        <BaseNode className="w-72">
-            <BaseNodeHeader className="border-b">
-                <Code2 className="size-4" />
-                <BaseNodeHeaderTitle>{id}</BaseNodeHeaderTitle>
-            </BaseNodeHeader>
+        <BaseNode className="min-w-72 min-h-[260px]" dimensions={dimensions} resizable nodeId={id} handles={<><InputHandle id="in" /><OutputHandle id="out" /></>}>
+            <BaseNodeHeaderRow icon={<Code2 className="size-4" />} title={id} />
 
             <BaseNodeContent>
-                <p className="text-[10px] text-muted-foreground mb-1">
+                <p className="shrink-0 text-[10px] text-muted-foreground mb-1">
                     Call in config: <code className="rounded bg-muted px-0.5">$&#123;{id}(var1, var2)&#125;</code>
                 </p>
-                <div style={{ height: 120 }} className="w-full nodrag nopan overflow-hidden rounded border border-input">
+                <div ref={editorContainerRef} className="min-h-0 flex-1 w-full nodrag nopan overflow-hidden rounded border border-input">
                     <CodeMirror
                         value={value}
-                        height="120px"
+                        height={`${editorHeight}px`}
                         theme={theme}
                         extensions={extensions}
                         onChange={onChange}
@@ -78,13 +83,8 @@ export const FunctionNode = memo(function FunctionNode({ id, data }: Props) {
             </BaseNodeContent>
 
             <BaseNodeFooter>
-                <div className="w-full text-xs text-muted-foreground">
-                    Body: {storedBody ? `${storedBody.length} chars` : 'none'}
-                </div>
+                <BaseNodeFooterText>Body: {storedBody ? `${storedBody.length} chars` : 'none'}</BaseNodeFooterText>
             </BaseNodeFooter>
-
-            <InputHandle id="in" />
-            <OutputHandle id="out" />
         </BaseNode>
     )
 })

src/components/graph/RenderingNode.tsx

@@ -6,8 +6,8 @@ import {
     BaseNode,
     BaseNodeContent,
     BaseNodeFooter,
-    BaseNodeHeader,
-    BaseNodeHeaderTitle,
+    BaseNodeFooterText,
+    BaseNodeHeaderRow,
 } from './BaseNode'
 import { Sparkles } from 'lucide-react'
 import { InputHandle, OutputHandle } from './NodeHandles'
@@ -18,8 +18,11 @@ const KROKI_PLANTUML_SVG = '/api/kroki/plantuml/svg'
 type Props = {
     id: string
     data?: any
+    style?: React.CSSProperties
 }
 
+const DEFAULT_CONFIG_NODE_STYLE = { width: 320, height: 320 }
+
 const DARK_SKINPARAMS = `
 skinparam backgroundColor #1e1e1e
 skinparam defaultFontColor #e0e0e0
@@ -63,7 +66,7 @@ skinparam class {
 }
 `
 
-export const RenderingNode = memo(function RenderingNode({ id }: Props) {
+export const RenderingNode = memo(function RenderingNode({ id, width, height }: Props) {
     const [svgContent, setSvgContent] = useState<string | null>(null)
     const [error, setError] = useState<null | { kind: string; message: string }>(null)
     const [loading, setLoading] = useState(false)
@@ -263,69 +266,70 @@ export const RenderingNode = memo(function RenderingNode({ id }: Props) {
         // Do not depend on nodes/edges refs to avoid flicker from unnecessary re-renders.
     }, [id, theme, plantumlText, configSignature, edgesSignature, variablesSignature, functionsSignature])
 
+    const dimensions =
+        width != null && height != null && width > 0 && height > 0
+            ? { width, height }
+            : undefined
+
     return (
-        <BaseNode className="w-96">
-            <BaseNodeHeader className="border-b">
-                <Sparkles className="size-4" />
-                <BaseNodeHeaderTitle>{id}</BaseNodeHeaderTitle>
-            </BaseNodeHeader>
+        <BaseNode className="min-w-96 min-h-[320px]" dimensions={dimensions} resizable nodeId={id} handles={<><InputHandle id="ain" /><OutputHandle id="out" /></>}>
+            <BaseNodeHeaderRow icon={<Sparkles className="size-4" />} title={id} />
 
             <BaseNodeContent>
-                {incomingIds.length === 0 ? (
-                    <Empty>
-                        <EmptyHeader>
-                            <EmptyMedia variant="icon">
-                                <Sparkles className="size-6" />
-                            </EmptyMedia>
-                            <EmptyTitle>No configuration connected</EmptyTitle>
-                            <EmptyDescription>Connect a Configuration node or create one. The renderer will display the PlantUML diagram.</EmptyDescription>
-                        </EmptyHeader>
-                        <EmptyContent>
-                            <button
-                                className="inline-flex items-center rounded bg-primary px-3 py-1 text-xs text-primary-foreground"
-                                onClick={() => {
-                                    if (!setNodes || !setEdges) return
-                                    const genId = () => `node_${Math.random().toString(36).slice(2, 9)}`
-                                    const nid = genId()
-                                    const thisNode = nodes.find((n: any) => n.id === id)
-                                    const pos = thisNode?.position ?? { x: 0, y: 0 }
-                                    const newPos = { x: pos.x - 220, y: pos.y }
-                                    const newNode = { id: nid, type: 'config', position: newPos, data: { plantuml: '@startuml\n\n@enduml\n', title: `config-${nid}` } }
-                                    setNodes((nds: any[]) => nds.concat(newNode))
-                                    const edgeId = `e-${nid}-${id}`
-                                    setEdges((eds: any[]) => eds.concat({ id: edgeId, source: nid, target: id }))
-                                }}
-                            >
-                                Create Config
-                            </button>
-                        </EmptyContent>
-                    </Empty>
-                ) : error ? (
-                    srcData?.renderError ? (
-                        srcData.renderError(error)
-                    ) : srcData?.errorHtml ? (
-                        <div className="p-3 text-xs text-red-700 dark:text-red-400" dangerouslySetInnerHTML={{ __html: String(srcData.errorHtml) }} />
-                    ) : (
-                        <div className="p-3 text-xs text-red-700 dark:text-red-400">{error.message}</div>
-                    )
-                ) : loading ? (
-                    <div className="flex min-h-[120px] items-center justify-center text-xs text-muted-foreground">Rendering…</div>
-                ) : svgContent ? (
-                    <div
-                        className="min-h-[120px] w-full overflow-auto rounded border border-input bg-white dark:bg-gray-900 [&_svg]:max-w-full [&_svg]:h-auto"
-                        dangerouslySetInnerHTML={{ __html: svgContent }}
-                    />
-                ) : null}
+                <div className="min-h-0 flex-1 flex flex-col">
+                    {incomingIds.length === 0 ? (
+                        <Empty className="min-h-0 flex-1">
+                            <EmptyHeader>
+                                <EmptyMedia variant="icon">
+                                    <Sparkles className="size-6" />
+                                </EmptyMedia>
+                                <EmptyTitle>No configuration connected</EmptyTitle>
+                                <EmptyDescription>Connect a Configuration node or create one. The renderer will display the PlantUML diagram.</EmptyDescription>
+                            </EmptyHeader>
+                            <EmptyContent>
+                                <button
+                                    className="inline-flex items-center rounded bg-primary px-3 py-1 text-xs text-primary-foreground"
+                                    onClick={() => {
+                                        if (!setNodes || !setEdges) return
+                                        const genId = () => `node_${Math.random().toString(36).slice(2, 9)}`
+                                        const nid = genId()
+                                        const thisNode = nodes.find((n: any) => n.id === id)
+                                        const pos = thisNode?.position ?? { x: 0, y: 0 }
+                                        const newPos = { x: pos.x - 220, y: pos.y }
+                                        const newNode = { id: nid, type: 'config', position: newPos, data: { plantuml: '@startuml\n\n@enduml\n', title: `config-${nid}` }, style: DEFAULT_CONFIG_NODE_STYLE }
+                                        setNodes((nds: any[]) => nds.concat(newNode))
+                                        const edgeId = `e-${nid}-${id}`
+                                        setEdges((eds: any[]) => eds.concat({ id: edgeId, source: nid, target: id }))
+                                    }}
+                                >
+                                    Create Config
+                                </button>
+                            </EmptyContent>
+                        </Empty>
+                    ) : error ? (
+                        srcData?.renderError ? (
+                            srcData.renderError(error)
+                        ) : srcData?.errorHtml ? (
+                            <div className="p-3 text-xs text-red-700 dark:text-red-400" dangerouslySetInnerHTML={{ __html: String(srcData.errorHtml) }} />
+                        ) : (
+                            <div className="p-3 text-xs text-red-700 dark:text-red-400">{error.message}</div>
+                        )
+                    ) : loading ? (
+                        <div className="flex min-h-0 flex-1 items-center justify-center text-xs text-muted-foreground">Rendering…</div>
+                    ) : svgContent ? (
+                        <div
+                            className="min-h-0 flex-1 w-full overflow-auto rounded border border-input bg-white dark:bg-gray-900 [&_svg]:max-w-full [&_svg]:h-auto"
+                            dangerouslySetInnerHTML={{ __html: svgContent }}
+                        />
+                    ) : null}
+                </div>
             </BaseNodeContent>
 
             <BaseNodeFooter>
-                <div className="w-full text-xs text-muted-foreground">
+                <BaseNodeFooterText>
                     {svgContent ? 'PlantUML diagram' : error ? 'Error' : '—'}
-                </div>
+                </BaseNodeFooterText>
             </BaseNodeFooter>
-
-            <InputHandle id="ain" />
-            <OutputHandle id="out" />
         </BaseNode>
     )
 })

src/components/graph/VariableNode.tsx

@@ -3,8 +3,9 @@ import FlowContext from '../../lib/flowContext'
 import {
     BaseNode,
     BaseNodeContent,
-    BaseNodeHeader,
-    BaseNodeHeaderTitle,
+    BaseNodeFooter,
+    BaseNodeFooterText,
+    BaseNodeHeaderRow,
 } from './BaseNode'
 import { Input } from '../ui/input'
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '../ui/select'
@@ -88,11 +89,8 @@ export const VariableNode = memo(function VariableNode({ id, data }: Props) {
     )
 
     return (
-        <BaseNode className="w-56">
-            <BaseNodeHeader className="border-b">
-                <Variable className="size-4" />
-                <BaseNodeHeaderTitle>{id}</BaseNodeHeaderTitle>
-            </BaseNodeHeader>
+        <BaseNode className="min-w-56 min-h-[180px]" handles={<OutputHandle id="out" />}>
+            <BaseNodeHeaderRow icon={<Variable className="size-4" />} title={id} />
 
             <BaseNodeContent className="gap-2 p-3">
                 <div className="flex flex-col gap-1.5">
@@ -126,12 +124,13 @@ export const VariableNode = memo(function VariableNode({ id, data }: Props) {
                         />
                     )}
                 </div>
-                <p className="text-[10px] text-muted-foreground">
-                    Use in config: <code className="rounded bg-muted px-0.5">prop: $&#123;{id}&#125;</code>
-                </p>
             </BaseNodeContent>
 
-            <OutputHandle id="out" />
+            <BaseNodeFooter>
+                <BaseNodeFooterText>
+                    Use in config: <code className="rounded bg-muted px-0.5">prop: {'${'}{id}{'}'}</code>
+                </BaseNodeFooterText>
+            </BaseNodeFooter>
         </BaseNode>
     )
 })

src/hooks/useResizeHeight.ts

@@ -0,0 +1,27 @@
+import { useEffect, useRef, useState } from 'react'
+
+/**
+ * Returns the height of the observed element, updating when it resizes (e.g. node resize).
+ * Used to give CodeMirror and other components an explicit height that tracks their container.
+ */
+export function useResizeHeight(defaultHeight: number): [number, React.RefObject<HTMLDivElement | null>] {
+    const ref = useRef<HTMLDivElement | null>(null)
+    const [height, setHeight] = useState(defaultHeight)
+
+    useEffect(() => {
+        const el = ref.current
+        if (!el) return
+
+        const ro = new ResizeObserver((entries) => {
+            const entry = entries[0]
+            if (entry?.contentRect.height != null && entry.contentRect.height > 0) {
+                setHeight(entry.contentRect.height)
+            }
+        })
+        ro.observe(el)
+        setHeight(el.getBoundingClientRect().height)
+        return () => ro.disconnect()
+    }, [])
+
+    return [height, ref]
+}

src/styles.css

@@ -51,6 +51,18 @@ body {
     }
 }
 
+/* Resize control: snappy drag, no transition or selection delay */
+.react-flow__resize-control.bottom.right {
+    cursor: se-resize;
+    touch-action: none;
+    user-select: none;
+}
+
+.react-flow__resize-control.bottom.right,
+.react-flow__resize-control.bottom.right * {
+    transition: none;
+}
+
 /* Small helper for monospace pre output */
 pre {
     font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, 'Roboto Mono', 'Courier New', monospace;