diff --git a/app/common/TableData.ts b/app/common/TableData.ts
index b3c8f76a..55b39d7f 100644
--- a/app/common/TableData.ts
+++ b/app/common/TableData.ts
@@ -251,21 +251,16 @@ export class TableData extends ActionDispatcher {
     return records;
   }
 
+  public filterRowIds(properties: {[key: string]: any}): number[] {
+    return this._filterRowIndices(properties).map(i => this._rowIdCol[i]);
+  }
+
   /**
    * Builds and returns the list of records in this table that match the given properties object.
    * Properties may include 'id' and any table columns. Returned records are not sorted.
    */
   public filterRecords(properties: {[key: string]: any}): RowRecord[] {
-    const rowIndices: number[] = [];
-    // Pairs of [valueToMatch, arrayOfColValues]
-    const props = Object.keys(properties).map(p => [properties[p], this._columns.get(p)]);
-    this._rowIdCol.forEach((id, i) => {
-      for (const p of props) {
-        if (p[1].values[i] !== p[0]) { return; }
-      }
-      // Collect the indices of the matching rows.
-      rowIndices.push(i);
-    });
+    const rowIndices: number[] = this._filterRowIndices(properties);
 
     // Convert the array of indices to an array of RowRecords.
     const records: RowRecord[] = rowIndices.map(i => ({id: this._rowIdCol[i]}));
@@ -289,6 +284,20 @@ export class TableData extends ActionDispatcher {
     return index < 0 ? 0 : this._rowIdCol[index];
   }
 
+  /**
+   * Returns the first rowId matching the given filters, or 0 if no match. If there are multiple
+   * matches, it is unspecified which will be returned.
+   */
+  public findMatchingRowId(properties: {[key: string]: CellValue}): number {
+    const props = Object.keys(properties).map(p => ({col: this._columns.get(p)!, value: properties[p]}));
+    if (!props.every((p) => p.col)) {
+      return 0;
+    }
+    return this._rowIdCol.find((id, i) =>
+      props.every((p) => (p.col.values[i] === p.value))
+    ) || 0;
+  }
+
   /**
    * Applies a DocAction received from the server; returns true, or false if it was skipped.
    */
@@ -419,6 +428,19 @@ export class TableData extends ActionDispatcher {
     // Stop dispatching actions if we've been deleted. We might also want to clean up in the future.
     this._isLoaded = false;
   }
+
+  private _filterRowIndices(properties: {[key: string]: any}): number[] {
+    const rowIndices: number[] = [];
+    // Array of {col: arrayOfColValues, value: valueToMatch}
+    const props = Object.keys(properties).map(p => ({col: this._columns.get(p)!, value: properties[p]}));
+    this._rowIdCol.forEach((id, i) => {
+      // Collect the indices of the matching rows.
+      if (props.every((p) => (p.col.values[i] === p.value))) {
+        rowIndices.push(i);
+      }
+    });
+    return rowIndices;
+  }
 }
 
 function reassignArray<T>(targetArray: T[], sourceArray: T[]): void {
diff --git a/app/common/gristUrls.ts b/app/common/gristUrls.ts
index eb69d441..4e84ac0f 100644
--- a/app/common/gristUrls.ts
+++ b/app/common/gristUrls.ts
@@ -66,6 +66,7 @@ export interface IGristUrlState {
     embed?: boolean;
     style?: InterfaceStyle;
     compare?: string;
+    aclUI?: boolean;
   };
   hash?: HashLink;   // if present, this specifies an individual row within a section of a page.
 }
@@ -260,6 +261,9 @@ export function decodeUrl(gristConfig: Partial<GristLoadConfig>, location: Locat
   if (sp.has('compare')) {
     state.params!.compare = sp.get('compare')!;
   }
+  if (sp.has('aclUI')) {
+    state.params!.aclUI = isAffirmative(sp.get('aclUI'));
+  }
   if (location.hash) {
     const hash = location.hash;
     const hashParts = hash.split('.');
diff --git a/app/server/lib/GranularAccess.ts b/app/server/lib/GranularAccess.ts
index 80319599..fa7b85fa 100644
--- a/app/server/lib/GranularAccess.ts
+++ b/app/server/lib/GranularAccess.ts
@@ -75,6 +75,7 @@ export class GranularAccess {
   public update() {
     this._resources = this._docData.getTable('_grist_ACLResources')!;
     this._ownerOnlyTableIds.clear();
+    this._onlyOwnersCanModifyStructure = false;
     for (const res of this._resources.getRecords()) {
       const code = String(res.colIds);
       if (res.tableId && code === '~o') {