Keep dataflow nodes initialized

webui/scripts/test-dataflow-page-structure.mjs

@@ -14,6 +14,8 @@ const checks = [
   [canvas.includes("application/x-govoplan-dataflow-node"), "palette drop handling"],
   [canvas.includes("isValidConnection"), "edge validation"],
   [canvas.includes("connectionRadius={32}"), "visible connection drop radius"],
+  [canvas.includes("initialWidth: 180"), "known initial node width"],
+  [canvas.includes('change.type !== "dimensions"'), "measurement-only change filtering"],
   [
     moduleEntry.indexOf("@xyflow/react/dist/style.css") <
       moduleEntry.indexOf("./styles/dataflow.css"),

webui/src/features/dataflow/DataflowCanvas.tsx

@@ -69,6 +69,8 @@ export default function DataflowCanvas({
         id: node.id,
         type: "dataflow",
         position: node.position,
+        initialWidth: 180,
+        initialHeight: node.type.startsWith("combine.") ? 64 : 54,
         selected: node.id === selectedNodeId,
         data: {
           label: node.label,
@@ -180,7 +182,10 @@ export default function DataflowCanvas({
         onInit={setInstance}
         onNodesChange={(changes) => {
           if (readOnly) return;
-          updateNodes(applyNodeChanges(changes, nodes));
+          const graphChanges = changes.filter((change) => change.type !== "dimensions");
+          if (graphChanges.length) {
+            updateNodes(applyNodeChanges(graphChanges, nodes));
+          }
         }}
         onEdgesChange={(changes) => {
           if (readOnly) return;