Header removals wait for the code editor to be left: autosave saves with drop=false, so follow_header adds and renames from the header but keeps a port or setting whose parameter is gone, and leaving the editor (blur or closing the panel) saves once more with removals; source saves of a flow run one at a time

frontend/src/components/Flow/NodePanel.tsx

@@ -1409,7 +1409,8 @@ function PanelBody({
   expanded: boolean
   onChange: (next: NodeDef_Input) => void
   onRenameMessage: (previous: string, next: string) => void
-  onSaveSource: (code: string) => void
+  /** `drop` is false while the code is still being typed; see `settle`. */
+  onSaveSource: (code: string, drop: boolean) => void
   onShared: () => void
   onToggleExpand: () => void
 }) {
@@ -1431,6 +1432,7 @@ function PanelBody({
   // only overwrite the first.
   const portMove = useRef<[string, string | null] | null>(null)
   const timer = useRef<ReturnType<typeof setTimeout> | null>(null)
+  // Code typed since the editor was last left.
   const pending = useRef<string | null>(null)
   const save = useRef(onSaveSource)
   save.current = onSaveSource
@@ -1441,7 +1443,22 @@ function PanelBody({
       clearTimeout(timer.current)
       timer.current = null
     }
-    if (pending.current !== null) save.current(pending.current)
+    if (pending.current !== null) save.current(pending.current, false)
+  }
+
+  /**
+   * The editor was left, so the code is saved once more, now dropping the
+   * ports and settings its header no longer names. Saves while typing only
+   * add and rename, so a parameter deleted mid-edit keeps its port and
+   * message until then, and typing it back changes nothing.
+   */
+  const settle = () => {
+    if (timer.current) {
+      clearTimeout(timer.current)
+      timer.current = null
+    }
+    if (pending.current !== null) save.current(pending.current, true)
+    pending.current = null
   }
 
   const editCode = (next: string) => {
@@ -1450,7 +1467,7 @@ function PanelBody({
     if (timer.current) clearTimeout(timer.current)
     timer.current = setTimeout(() => {
       timer.current = null
-      save.current(next)
+      save.current(next, false)
     }, 1000)
   }
 
@@ -1520,13 +1537,13 @@ function PanelBody({
     ["mod+s"],
   )
 
-  // Closing the panel must not lose the last keystrokes.
+  // Closing the panel leaves the editor too, and must not lose the last
+  // keystrokes.
   useEffect(() => {
     return () => {
-      if (timer.current) {
-        clearTimeout(timer.current)
-        if (pending.current !== null) save.current(pending.current)
-      }
+      if (timer.current) clearTimeout(timer.current)
+      if (pending.current !== null) save.current(pending.current, true)
+      pending.current = null
     }
   }, [])
 
@@ -1704,6 +1721,7 @@ function PanelBody({
               <NodeEditor
                 value={code ?? source?.code ?? ""}
                 onChange={editCode}
+                onBlur={settle}
                 readOnly={Boolean(origin) || !mayEditCode}
               />
             </Suspense>
@@ -1745,7 +1763,7 @@ export function NodePanel({
   expanded: boolean
   onChange: (next: NodeDef_Input) => void
   onRenameMessage: (previous: string, next: string) => void
-  onSaveSource: (code: string) => void
+  onSaveSource: (code: string, drop: boolean) => void
   onShared: () => void
   onToggleExpand: () => void
   onClose: () => void