diff --git a/src/PivotTableUI.jsx b/src/PivotTableUI.jsx
index 0de055f..0010c0f 100644
--- a/src/PivotTableUI.jsx
+++ b/src/PivotTableUI.jsx
@@ -210,6 +210,7 @@ export class Dropdown extends React.PureComponent {
                     this.props.toggle();
                   } else {
                     this.props.setValue(r);
+                    this.props.toggle(); // Close the dropdown after selection
                   }
                 }}
                 className={
@@ -284,12 +285,38 @@ class PivotTableUI extends React.PureComponent {
     this.setState(newState);
   }
 
+  handleDuplicates(newAttributes, existingAttributes) {
+    if (!newAttributes || !existingAttributes) {
+      return existingAttributes || [];
+    }
+    const duplicates = newAttributes.filter(item => existingAttributes.includes(item));
+    return duplicates.length > 0 
+      ? existingAttributes.filter(item => !duplicates.includes(item))
+      : existingAttributes;
+  }
+
   sendPropUpdate(command) {
     this.props.onChange(update(this.props, command));
   }
 
   propUpdater(key) {
-    return value => this.sendPropUpdate({[key]: {$set: value}});
+    return value => {
+      const update = {[key]: {$set: value}};
+
+      if (key === 'rows') {
+        const updatedCols = this.handleDuplicates(value, this.props.cols);
+        if (updatedCols.length !== this.props.cols.length) {
+          update.cols = {$set: updatedCols};
+        }
+      } else if (key === 'cols') {
+        const updatedRows = this.handleDuplicates(value, this.props.rows);
+        if (updatedRows.length !== this.props.rows.length) {
+          update.rows = {$set: updatedRows};
+        }
+      }
+  
+      this.sendPropUpdate(update);
+    };
   }
 
   setValuesInFilter(attribute, values) {
@@ -502,7 +529,6 @@ class PivotTableUI extends React.PureComponent {
         !this.props.hiddenAttributes.includes(e) &&
         !this.props.hiddenFromDragDrop.includes(e)
     );
-
     const colAttrsCell = this.makeDnDCell(
       colAttrs,
       this.propUpdater('cols'),
@@ -519,6 +545,7 @@ class PivotTableUI extends React.PureComponent {
       this.propUpdater('rows'),
       'pvtAxisContainer pvtVertList pvtRows'
     );
+    
     const outputCell = (
       <td className="pvtOutput">
         <PivotTable
diff --git a/src/__tests__/PivotTableUI-test.js b/src/__tests__/PivotTableUI-test.js
new file mode 100644
index 0000000..58ea80e
--- /dev/null
+++ b/src/__tests__/PivotTableUI-test.js
@@ -0,0 +1,190 @@
+import React from 'react';
+import PivotTableUI from '../PivotTableUI';
+
+describe('PivotTableUI', () => {
+  describe('handleDuplicates', () => {
+    // Create a minimal instance of PivotTableUI for testing
+    const getInstance = () => {
+      const pivotTableUI = new PivotTableUI({
+        onChange: () => {},
+        renderers: {},
+        aggregators: {},
+        rows: [],
+        cols: [],
+        rendererName: '',
+        aggregatorName: '',
+        vals: [],
+        valueFilter: {},
+        rowOrder: 'key_a_to_z',
+        colOrder: 'key_a_to_z',
+        derivedAttributes: {},
+        data: []
+      });
+      return pivotTableUI;
+    };
+
+    it('returns existingAttributes when newAttributes is null or undefined', () => {
+      const instance = getInstance();
+      expect(instance.handleDuplicates(null, ['a', 'b'])).toEqual(['a', 'b']);
+      expect(instance.handleDuplicates(undefined, ['a', 'b'])).toEqual(['a', 'b']);
+    });
+
+    it('returns empty array when both inputs are null or undefined', () => {
+      const instance = getInstance();
+      expect(instance.handleDuplicates(null, null)).toEqual([]);
+      expect(instance.handleDuplicates(undefined, undefined)).toEqual([]);
+    });
+
+    it('returns existingAttributes when there are no duplicates', () => {
+      const instance = getInstance();
+      const newAttributes = ['a', 'b', 'c'];
+      const existingAttributes = ['d', 'e', 'f'];
+      expect(instance.handleDuplicates(newAttributes, existingAttributes))
+        .toEqual(existingAttributes);
+    });
+
+    it('removes duplicates from existingAttributes', () => {
+      const instance = getInstance();
+      const newAttributes = ['a', 'b', 'c'];
+      const existingAttributes = ['b', 'c', 'd'];
+      // 'b' and 'c' are duplicates and should be removed
+      expect(instance.handleDuplicates(newAttributes, existingAttributes))
+        .toEqual(['d']);
+    });
+
+    it('handles empty newAttributes', () => {
+      const instance = getInstance();
+      const newAttributes = [];
+      const existingAttributes = ['a', 'b', 'c'];
+      expect(instance.handleDuplicates(newAttributes, existingAttributes))
+        .toEqual(existingAttributes);
+    });
+
+    it('handles empty existingAttributes', () => {
+      const instance = getInstance();
+      const newAttributes = ['a', 'b', 'c'];
+      const existingAttributes = [];
+      expect(instance.handleDuplicates(newAttributes, existingAttributes))
+        .toEqual([]);
+    });
+
+    it('handles case with all attributes being duplicates', () => {
+      const instance = getInstance();
+      const newAttributes = ['a', 'b', 'c'];
+      const existingAttributes = ['a', 'b', 'c'];
+      expect(instance.handleDuplicates(newAttributes, existingAttributes))
+        .toEqual([]);
+    });
+  });
+
+  describe('propUpdater', () => {
+    // We'll use a mock to check if sendPropUpdate is called with the right arguments
+    let mockSendPropUpdate;
+    let instance;
+
+    beforeEach(() => {
+      instance = new PivotTableUI({
+        onChange: () => {},
+        renderers: {},
+        aggregators: {},
+        rows: ['gender', 'age'],
+        cols: ['country', 'year'],
+        rendererName: '',
+        aggregatorName: '',
+        vals: [],
+        valueFilter: {},
+        rowOrder: 'key_a_to_z',
+        colOrder: 'key_a_to_z',
+        derivedAttributes: {},
+        data: []
+      });
+      // Mock the sendPropUpdate method
+      mockSendPropUpdate = jest.spyOn(instance, 'sendPropUpdate').mockImplementation(() => {});
+      // Mock the handleDuplicates method to control its return value
+      jest.spyOn(instance, 'handleDuplicates');
+    });
+
+    afterEach(() => {
+      mockSendPropUpdate.mockRestore();
+      instance.handleDuplicates.mockRestore();
+    });
+
+    it('calls handleDuplicates when key is "rows"', () => {
+      const newRows = ['gender', 'name'];
+      const updater = instance.propUpdater('rows');
+      
+      // Set up the mock to return the same cols (no duplicates found)
+      instance.handleDuplicates.mockReturnValueOnce(instance.props.cols);
+      
+      updater(newRows);
+      
+      expect(instance.handleDuplicates).toHaveBeenCalledWith(newRows, instance.props.cols);
+      expect(mockSendPropUpdate).toHaveBeenCalledWith({
+        rows: { $set: newRows }
+      });
+    });
+
+    it('calls handleDuplicates when key is "cols"', () => {
+      const newCols = ['country', 'city'];
+      const updater = instance.propUpdater('cols');
+      
+      // Set up the mock to return the same rows (no duplicates found)
+      instance.handleDuplicates.mockReturnValueOnce(instance.props.rows);
+      
+      updater(newCols);
+      
+      expect(instance.handleDuplicates).toHaveBeenCalledWith(newCols, instance.props.rows);
+      expect(mockSendPropUpdate).toHaveBeenCalledWith({
+        cols: { $set: newCols }
+      });
+    });
+
+    it('updates cols when duplicate is found in rows update', () => {
+      const newRows = ['gender', 'country']; // 'country' is duplicate
+      const updater = instance.propUpdater('rows');
+      
+      // 'country' is removed from cols
+      const updatedCols = ['year'];
+      instance.handleDuplicates.mockReturnValueOnce(updatedCols);
+      
+      updater(newRows);
+      
+      expect(mockSendPropUpdate).toHaveBeenCalledWith({
+        rows: { $set: newRows },
+        cols: { $set: updatedCols }
+      });
+    });
+
+    it('updates rows when duplicate is found in cols update', () => {
+      const newCols = ['country', 'gender']; // 'gender' is duplicate
+      const updater = instance.propUpdater('cols');
+      
+      // 'gender' is removed from rows
+      const updatedRows = ['age'];
+      instance.handleDuplicates.mockReturnValueOnce(updatedRows);
+      
+      updater(newCols);
+      
+      expect(mockSendPropUpdate).toHaveBeenCalledWith({
+        cols: { $set: newCols },
+        rows: { $set: updatedRows }
+      });
+    });
+
+    it('does not update the other attribute if no duplicates found', () => {
+      const newRows = ['gender', 'name'];
+      const updater = instance.propUpdater('rows');
+      
+      // No change to cols (same array reference)
+      instance.handleDuplicates.mockReturnValueOnce(instance.props.cols);
+      
+      updater(newRows);
+      
+      expect(mockSendPropUpdate).toHaveBeenCalledWith({
+        rows: { $set: newRows }
+      });
+      // We shouldn't have cols in the update
+      expect(mockSendPropUpdate.mock.calls[0][0].cols).toBeUndefined();
+    });
+  });
+});