diff --git a/DataPlotly/core/plot_expressions.py b/DataPlotly/core/plot_expressions.py
new file mode 100644
index 00000000..55d7e133
--- /dev/null
+++ b/DataPlotly/core/plot_expressions.py
@@ -0,0 +1,53 @@
+# -*- coding: utf-8 -*-
+"""
+/***************************************************************************
+ DataPlotly
+                                 A QGIS plugin
+ D3 Plots for QGIS
+                              -------------------
+        begin                : 2022-06-08
+        git sha              : $Format:%H$
+        copyright            : (C) 2020 by matteo ghetta
+        email                : matteo.ghetta@faunalia.it
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+"""
+
+from qgis.utils import qgsfunction, iface
+
+@qgsfunction(args='auto', group='DataPlotly')
+def get_categories_colors(field, feature, parent):
+    """
+        Retrieve the color of each category as html code. You can use this function
+        to set the plot items (pie slices, bars, points, etc) to the same color
+        of the feature visible in the map.
+        <h4>Syntax</h4>
+        <p>
+            get_categories_colors(categorization_field)
+        </p>
+        <h4>Arguments</h4>
+        <p><strong>categorization_field</strong>: the name of the field used in the categorization</p>
+        <h4>Example</h4>
+        <p>
+            get_categories_colors("CONTINENT") -> '#da1ddd'
+        </p>
+    """
+
+    layer = iface.activeLayer()
+    renderer = layer.renderer()
+  
+    if layer.renderer().type() == "categorizedSymbol":
+        for category in renderer.categories():
+            if field == category.value():
+                category_color = category.symbol().color().name()
+                break
+                
+    return category_color
\ No newline at end of file
diff --git a/DataPlotly/core/plot_factory.py b/DataPlotly/core/plot_factory.py
index 0c7e7735..59be929d 100644
--- a/DataPlotly/core/plot_factory.py
+++ b/DataPlotly/core/plot_factory.py
@@ -485,13 +485,11 @@ def js_callback(_):
         dds["type"] = data.points[0].data.type
 
         featureIds = [];
-        featureIdsTernary = [];
 
         data.points.forEach(function(pt){
-        featureIds.push(parseInt(pt.id))
-        featureIdsTernary.push(parseInt(pt.pointNumber))
+        featureIds.push(pt.x)
         dds["id"] = featureIds
-        dds["tid"] = featureIdsTernary
+        dds["field"] = pt.data.customdata[0]
             })
         //console.log(dds)
         window.status = JSON.stringify(dds)
@@ -511,6 +509,8 @@ def js_callback(_):
         if(data.points[i].data.type == 'scatter'){
             dd["uid"] = data.points[i].data.uid
             dd["type"] = data.points[i].data.type
+            dd["field"] = data.points[i].data.customdata[0]
+            dd["id"] = data.points[i].x
 
             data.points.forEach(function(pt){
             dd["fid"] = pt.id
diff --git a/DataPlotly/data_plotly.py b/DataPlotly/data_plotly.py
index 97e0e523..ea7c94a0 100644
--- a/DataPlotly/data_plotly.py
+++ b/DataPlotly/data_plotly.py
@@ -25,7 +25,7 @@
 from qgis.PyQt.QtCore import QSettings, QTranslator, QCoreApplication, Qt, QUrl
 from qgis.PyQt.QtGui import QDesktopServices
 from qgis.PyQt.QtWidgets import QAction
-from qgis.core import Qgis, QgsApplication
+from qgis.core import Qgis, QgsApplication, QgsExpression
 from qgis.gui import QgsGui
 
 # Import the code for the dialog
@@ -39,6 +39,9 @@
 from DataPlotly.layouts.plot_layout_item import PlotLayoutItemMetadata
 from DataPlotly.gui.layout_item_gui import PlotLayoutItemGuiMetadata
 
+# import custom expressions
+from .core.plot_expressions import get_categories_colors
+
 
 class DataPlotly:  # pylint: disable=too-many-instance-attributes
     """QGIS Plugin Implementation."""
@@ -132,6 +135,9 @@ def initGui(self):
             self.iface.pluginHelpMenu().addAction(self.help_action)
             self.help_action.triggered.connect(self.open_help)
 
+        # register the function
+        QgsExpression.registerFunction(get_categories_colors)
+
     def initProcessing(self):
         """Create the Processing provider"""
         QgsApplication.processingRegistry().addProvider(self.provider)
@@ -151,6 +157,9 @@ def unload(self):
         # Remove processing provider
         QgsApplication.processingRegistry().removeProvider(self.provider)
 
+        # unregister the function
+        QgsExpression.unregisterFunction('get_categories_colors')
+
     @staticmethod
     def open_help():
         """ Open the online help. """
diff --git a/DataPlotly/gui/plot_settings_widget.py b/DataPlotly/gui/plot_settings_widget.py
index 7d5780cf..b11095f4 100644
--- a/DataPlotly/gui/plot_settings_widget.py
+++ b/DataPlotly/gui/plot_settings_widget.py
@@ -475,15 +475,24 @@ def getJSmessage(self, status):
 
             # if a selection event is performed
             if dic['mode'] == 'selection':
+                exp = """ {} IN {} """.format(dic['field'], dic['id'])
+                exp = exp.replace('[', '(').replace(']', ')')
+                # set the iterator with the expression as filter in feature request
+                request = QgsFeatureRequest().setFilterExpression(exp)
+                it = self.layer_combo.currentLayer().getFeatures(request)
                 if dic['type'] == 'scatter':
-                    self.layer_combo.currentLayer().selectByIds(dic['id'])
+                    self.layer_combo.currentLayer().selectByIds([f.id() for f in it])
                 else:
-                    self.layer_combo.currentLayer().selectByIds(dic['tid'])
+                    self.layer_combo.currentLayer().selectByIds([f.id() for f in it])
 
             # if a clicking event is performed depending on the plot type
             elif dic["mode"] == 'clicking':
                 if dic['type'] == 'scatter':
-                    self.layer_combo.currentLayer().selectByIds([dic['fidd']])
+                    exp = """ {} = '{}' """.format(dic['field'], dic['id'])
+                    # set the iterator with the expression as filter in feature request
+                    request = QgsFeatureRequest().setFilterExpression(exp)
+                    it = self.layer_combo.currentLayer().getFeatures(request)
+                    self.layer_combo.currentLayer().selectByIds([f.id() for f in it])
                 elif dic["type"] == 'pie':
                     exp = """ "{}" = '{}' """.format(dic['field'], dic['label'])
                     # set the iterator with the expression as filter in feature request