diff --git a/lib/DataHarmonizer.js b/lib/DataHarmonizer.js
index 20187c60..576c47ea 100644
--- a/lib/DataHarmonizer.js
+++ b/lib/DataHarmonizer.js
@@ -763,14 +763,13 @@ class DataHarmonizer {
   }
 
   addRowsToBottom(numRows) {
-    console.log(this.context.currentSelection, numRows);
     // Get the starting row index where the new rows will be added
     const startRowIndex = this.hot.countRows();
 
     // Insert the new rows below the last existing row
-    this.hot.alter('insert_row_below', startRowIndex - 1, numRows);
+    this.hot.alter('insert_row_below', startRowIndex, numRows);
     // Validate and process the current selection
-    if (this.context.currentSelection !== null) {
+    if (this.context.currentSelection !== null && this.context.currentSelection.valueToMatch !== null) {
       // Find the nearest index after the last non-empty row in the specified column
       const baseColCoord = this.findNearestIndexAfterLastNonEmpty(0);
       this.populateNewRows(numRows, baseColCoord);
diff --git a/lib/utils/1m.js b/lib/utils/1m.js
index de60878e..3973497f 100644
--- a/lib/utils/1m.js
+++ b/lib/utils/1m.js
@@ -141,6 +141,25 @@ const findUniqueKeysForClass = (schema) => (cls_key) => {
   return unique_keys_acc;
 };
 
+const findActiveDataHarmonizer = appContext => {
+  // active = focused
+  let active_dh = null;
+  for (let dh_name in appContext) {
+    if (appContext[dh_name].active) {
+      active_dh = dh_name;
+      break;
+    }
+  }
+  return active_dh;
+};
+
+const setActiveDataHarmonizer = appContext => active_dh_name => {
+  for (let dh_name in appContext) {
+    appContext[dh_name].active = false;
+  }
+  appContext[active_dh_name].active = true;
+}
+
 const add_child_classes_to_unique_keys_for_appContext = appContext => {
   for (let dh_class_name in appContext) {
     for (let key in appContext[dh_class_name].unique_keys) {
@@ -237,7 +256,6 @@ Later we can add an efficiency function that the filtering of records isn’t pe
 const handsontableUpdateRouter = (appContext) => (dhs) => {
   document.addEventListener('handsontableUpdate', (event) => {
     const { emitted_by, key_name, action, target } = event.detail;
-    // TOOD: appContext is being cached? pbv?
 
     const classCanFire = emitted_by in appContext && key_name in appContext[emitted_by].unique_keys;
     const unique_key = appContext[emitted_by]?.unique_keys[key_name];
@@ -250,21 +268,22 @@ const handsontableUpdateRouter = (appContext) => (dhs) => {
         console.groupEnd();
         event.detail.target = emitted_by;
         handleAction(appContext)(dhs[emitted_by])(action, event.detail);
-        triggerCurrentSelection(makeCurrentSelection(appContext)(dhs[emitted_by]));
+        triggerCurrentSelection(makeCurrentSelection(appContext)(dhs[findActiveDataHarmonizer(appContext)]));
       } else if (action === ACTION.FILTER) {
-        console.log('reading', ACTION.FILTER, event.detail);
+        event.detail.currentSelection = makeCurrentSelection(appContext)(dhs[findActiveDataHarmonizer(appContext)]);
         handleAction(appContext)(dhs[target])(action, event.detail);
-      } else if (classHasForeignKey || !STRATEGY && classHasChildClasses) {
+      } else if (classHasForeignKey || classHasChildClasses ) {
         console.groupEnd();
         // TODO: this code goes into an infinite loop? why?
         // TODO: can this be refactored to use namespaces for events?
-        if (classHasForeignKey) {
-          dhs[unique_key.foreign_key_class].hot.runHooks(
-            `classDataRowKeyChange`,
-            action,
-            event.detail
-          );
-        } else if (classHasChildClasses) {
+        // if (classHasForeignKey) {
+          // dhs[unique_key.foreign_key_class].hot.runHooks(
+          //   `classDataRowKeyChange`,
+          //   action,
+          //   event.detail
+          // );
+        // } else 
+        if (classHasChildClasses) {
           for (let dh_key of unique_key.child_classes) {
             const dh = dhs[dh_key];
             event.detail.target = dh_key;
@@ -600,30 +619,6 @@ const clearRow = (hot, rowIndex) => {
   }
 };
 
-function filterRowsByCondition(hotInstance, columnIndex, conditionFunction) {
-  const totalRows = hotInstance.countRows();  // Get total rows in the table
-  let rowsToHide = [];  // Array to store rows to hide
-
-  // Iterate through each row
-  for (let row = 0; row < totalRows; row++) {
-    // Get the value of the cell in the specified column
-    let cellValue = hotInstance.getDataAtCell(row, columnIndex);
-
-    // If the cell value does not satisfy the condition, add the row index to rowsToHide
-    if (!conditionFunction(cellValue)) {
-      rowsToHide.push(row);
-    }
-  }
-
-  // Use the hiddenRows plugin to hide the rows
-  const hiddenRowsPlugin = hotInstance.getPlugin('hiddenRows');
-  hiddenRowsPlugin.showRows(hiddenRowsPlugin.getHiddenRows()); // Reset any previously hidden rows
-  hiddenRowsPlugin.hideRows(rowsToHide); // Hide the rows that don't meet the condition
-
-  // Render the table to apply changes
-  hotInstance.render();
-}
-
 const handleChange = (hot, [col, oldVal, newVal]) => {
   hot.batch(() => {
     const data = hot.getSourceData();
@@ -659,6 +654,52 @@ const triggerCurrentSelection = (currentSelection) => {
     $(document).trigger('dhCurrentSelectionChange', { currentSelection });
 }
 
+function filterRowsMatchingValueAtColumn(dh, columnIndex, valueToMatch) {
+  const hotInstance = dh.hot;
+  // Use the hiddenRows plugin to hide the rows
+  const hiddenRowsPlugin = hotInstance.getPlugin('hiddenRows');
+  console.warn('filterRowsMatchingValueAtColumn', hiddenRowsPlugin.getHiddenRows());
+  const totalRows = hotInstance.countRows();  // Get total rows in the table
+  hiddenRowsPlugin.showRows(hiddenRowsPlugin.getHiddenRows()); // Reset any previously hidden rows
+  
+
+  let rowsToHide = [];  // Array to store rows to hide
+
+  // Iterate through each row
+  for (let row = 0; row < totalRows; row++) {
+    // Get the value of the cell in the specified column
+    let cellValue = hotInstance.getDataAtCell(row, columnIndex);
+    console.warn(row, columnIndex, cellValue, valueToMatch);
+    // If the cell value does not satisfy the condition, add the row index to rowsToHide
+    if (cellValue !== valueToMatch) {
+      rowsToHide.push(row);
+    }
+  }
+
+  hiddenRowsPlugin.hideRows(rowsToHide); // Hide the rows that don't meet the condition
+
+  // Render the table to apply changes
+  hotInstance.render();
+}
+
+function filterAllRows(dh) {
+  const hotInstance = dh.hot;
+  // Use the hiddenRows plugin to hide the rows
+  const hiddenRowsPlugin = hotInstance.getPlugin('hiddenRows');
+  console.warn('filterAllRows', hiddenRowsPlugin.getHiddenRows());
+
+  hiddenRowsPlugin.showRows(hiddenRowsPlugin.getHiddenRows()); // Reset any previously hidden rows
+  const totalRows = hotInstance.countRows();  // Get total rows in the table
+  let numbers = [];
+  for (let i = 0; i < totalRows; i++) {
+    numbers.push(i);
+  }
+  hiddenRowsPlugin.hideRows(numbers); // Hide the rows that don't meet the condition
+
+  // Render the table to apply changes
+  hotInstance.render();
+}
+
 const handleAction = (appContext) => (dh) => (action, details) => {
   const {
     emitted_by,
@@ -688,6 +729,7 @@ const handleAction = (appContext) => (dh) => (action, details) => {
       if (col !== appContext[target].column && !isEmptyUnitVal(col)) {
         appContext[target].column = col;
       }
+      setActiveDataHarmonizer(appContext)(target);
       if ('child_classes' in shared_key_details) {
         for (let child_class of shared_key_details.child_classes) {
           console.log(child_class);
@@ -700,13 +742,13 @@ const handleAction = (appContext) => (dh) => (action, details) => {
       }
       break;
     case ACTION.FILTER:
-      console.log(ACTION.FILTER, emitted_by, dh.class_assignment, target, key_name);
-      const column = dh.getColumnIndexByFieldName(key_name);
-      filterRowsByCondition(
-        dh.hot,
-        column,
-        val => val === appContext[emitted_by].unique_keys[key_name],
-      );
+      const { currentSelection } = details;
+      console.warn(ACTION.FILTER, emitted_by, dh.class_assignment, target, key_name, currentSelection);
+      if (currentSelection.valueToMatch === null) {
+        filterAllRows(dh);
+      } else {
+        filterRowsMatchingValueAtColumn(dh, appContext[target].unique_keys[key_name].key_indexes[0], currentSelection.valueToMatch);
+      }
       break;
     case ACTION.UPDATE:
       // TODO: guaranteed to be the same length?
@@ -720,6 +762,7 @@ const handleAction = (appContext) => (dh) => (action, details) => {
           new_changes[col_index],
         ]);
       }
+      // read after update to update filters
       dispatchHandsontableUpdate(ACTION.READ, {
         ...details,
         key_name,
@@ -738,16 +781,16 @@ const handleAction = (appContext) => (dh) => (action, details) => {
 const bindActionHandler = (appContext) => (dh) => {
   // TODO: key in unique_keys?
   // TODO: pre-processing? check if the received event is from a proper child
-  if (STRATEGY) {
-    dh.hot.addHook('classDataRowKeyChange', (action, details) => {
-      console.log('handling action', action);
-      handleAction(appContext)(dh)(action, details);
-    });
-  } else {
-    dh.hot.addHook(`classDataRowKeyChange:${dh.class_assignment}`, (action, details) => {
-      handleAction(appContext)(dh)(action, details);
-    });
-  }
+  // if (STRATEGY) {
+  //   dh.hot.addHook('classDataRowKeyChange', (action, details) => {
+  //     console.log('handling action', action);
+  //     handleAction(appContext)(dh)(action, details);
+  //   });
+  // } else {
+  dh.hot.addHook(`classDataRowKeyChange:${dh.class_assignment}`, (action, details) => {
+    handleAction(appContext)(dh)(action, details);
+  });
+  // }
 };
 
 function createRowFocusTracker(hotInstance, onFocusChange) {
@@ -821,6 +864,7 @@ const makeCurrentSelection = appContext => dh => {
     shared_key_name: unique_keys[key_name].name, // TODO: translate to "is shared key"
     key_name,
     valueToMatch: maybeValueToMatch,
+    parentRow: row,
     parentCol: column
   };
 }