diff --git a/src/components/charts/DistributionPlot/DistributionPlot.re b/src/components/charts/DistributionPlot/DistributionPlot.re
index ecc52b09..bd85a66c 100644
--- a/src/components/charts/DistributionPlot/DistributionPlot.re
+++ b/src/components/charts/DistributionPlot/DistributionPlot.re
@@ -86,6 +86,21 @@ module Styles = {
       selector(".lollipops-x-axis .domain", [display(`none)]),
       selector(".lollipops-x-axis .tick line", [display(`none)]),
       selector(".lollipops-x-axis .tick text", [display(`none)]),
+      selector(
+        ".lollipop-tooltip",
+        [
+          position(`absolute),
+          textAlign(`center),
+          padding(px(2)),
+          backgroundColor(hex("bfcad4")),
+          borderRadius(px(3)),
+        ],
+      ),
+      selector(
+        ".lollipops-circle-mouseover",
+        [SVG.fill(hex("ffa500")), SVG.stroke(`hex("fff"))],
+      ),
+      selector(".lollipops-line-mouseover", [SVG.stroke(`hex("ffa500"))]),
     ]);
 };
 
@@ -126,4 +141,4 @@ let make =
       showVerticalLine
     />
   </div>;
-};
\ No newline at end of file
+};
diff --git a/src/components/charts/DistributionPlot/distPlotD3.js b/src/components/charts/DistributionPlot/distPlotD3.js
index 91250879..dfdc4af6 100644
--- a/src/components/charts/DistributionPlot/distPlotD3.js
+++ b/src/components/charts/DistributionPlot/distPlotD3.js
@@ -1,7 +1,11 @@
 const _ = require('lodash');
 const d3 = require('d3');
 const moment = require('moment');
+require('./styles.css');
 
+/**
+ * @todo: To rename as "DistPlotD3".
+ */
 export class CdfChartD3 {
 
   constructor() {
@@ -93,11 +97,11 @@ export class CdfChartD3 {
     // Add svg.
     this.svg = this._container
       .createObject({ tag: 'svg', selector: 'svg-chart-container' })
-      .attr('width', "100%")
+      .attr('width', '100%')
       .attr('height', this.attrs.svgHeight)
       .attr('pointer-events', 'none');
 
-    // Add container "g" (empty) element.
+    // Add container 'g' (empty) element.
     this.chart = this.svg
       .createObject({ tag: 'g', selector: 'chart' })
       .attr(
@@ -171,13 +175,13 @@ export class CdfChartD3 {
         .ticks(3)
         .tickFormat(d => {
           if (Math.abs(d) < 1) {
-            return d3.format(".2")(d);
+            return d3.format('.2')(d);
           } else if (xMin > 1000 && xMax < 3000) {
             // Condition which identifies years; 2019, 2020, 2021.
-            return d3.format(".0")(d);
+            return d3.format('.0')(d);
           } else {
-            const prefix = d3.formatPrefix(".0", d);
-            return prefix(d).replace("G", "B");
+            const prefix = d3.formatPrefix('.0', d);
+            return prefix(d).replace('G', 'B');
           }
         });
     }
@@ -314,32 +318,77 @@ export class CdfChartD3 {
       .domain([yMinDomain, yMaxDomain])
       .range([this.calc.chartHeight, 0]);
 
-    // Adds "g" for an y-axis.
+    // Adds 'g' for an y-axis.
     this.chart.append('g')
       .attr('class', 'lollipops-y-axis')
       .attr('transform', `translate(${this.calc.chartWidth}, 0)`)
       .call(d3.axisLeft(yScale));
 
+    function showTooltip(d) {
+      d3.select('#lollipops-line-' + d.id)
+        .classed('lollipops-line-mouseover', true);
+      d3.select('#lollipops-circle-' + d.id)
+        .classed('lollipops-circle-mouseover', true)
+        .attr('r', 6);
+      tooltip.transition()
+        .style('opacity', .9);
+      tooltip.html(`X: ${d.x}, Y: ${d.y}`)
+        .style('left', (distributionChart.xScale(d.x) + 60) + 'px')
+        .style('top', yScale(d.y) + 'px');
+    }
+
+    function hideTooltip(d) {
+      d3.select('#lollipops-line-' + d.id)
+        .classed('lollipops-line-mouseover', false);
+      d3.select('#lollipops-circle-' + d.id)
+        .classed('lollipops-circle-mouseover', false)
+        .attr('r', 4);
+      tooltip.transition()
+        .style('opacity', 0);
+    }
+
     // Lines.
     this.chart.selectAll('lollipops-line')
       .data(data)
       .enter()
       .append('line')
       .attr('class', 'lollipops-line')
+      .attr('id', d => 'lollipops-line-' + d.id)
       .attr('x1', d => distributionChart.xScale(d.x))
       .attr('x2', d => distributionChart.xScale(d.x))
       .attr('y1', d => yScale(d.y))
       .attr('y2', yScale(0));
 
+    // Define the div for the tooltip
+    const tooltip = this._container.append('div')
+      .attr('class', 'lollipop-tooltip')
+      .style('opacity', 0);
+
     // Circles.
     this.chart.selectAll('lollipops-circle')
       .data(data)
       .enter()
       .append('circle')
       .attr('class', 'lollipops-circle')
+      .attr('id', d => 'lollipops-circle-' + d.id)
       .attr('cx', d => distributionChart.xScale(d.x))
       .attr('cy', d => yScale(d.y))
       .attr('r', '4');
+
+    // Rectangles.
+    this.chart.selectAll('lollipops-rectangle')
+      .data(data)
+      .enter()
+      .append('rect')
+      .attr('width', 30)
+      .attr('height', this.calc.chartHeight)
+      .attr('x', d => distributionChart.xScale(d.x) - 15)
+      .attr('y', 0)
+      .attr('opacity', 0)
+      .attr('pointer-events', 'all')
+      .on('mouseover', showTooltip)
+      .on('mouseout', hideTooltip)
+    ;
   }
 
   /**
@@ -347,7 +396,7 @@ export class CdfChartD3 {
    * @returns {string}
    */
   formatDates(ts) {
-    return moment(ts).format("MMMM Do YYYY");
+    return moment(ts).format('MMMM Do YYYY');
   }
 
   /**
@@ -356,23 +405,23 @@ export class CdfChartD3 {
    */
   getTimeTicksByStr(unit) {
     switch (unit) {
-      case "months":
+      case 'months':
         return d3.timeMonth.every(4);
-      case "quarters":
+      case 'quarters':
         return d3.timeMonth.every(3);
-      case "hours":
+      case 'hours':
         return d3.timeHour.every(10);
-      case "days":
+      case 'days':
         return d3.timeDay.every(7);
-      case "seconds":
+      case 'seconds':
         return d3.timeSecond.every(10);
-      case "years":
+      case 'years':
         return d3.timeYear.every(10);
-      case "minutes":
+      case 'minutes':
         return d3.timeMinute.every(10);
-      case "weeks":
+      case 'weeks':
         return d3.timeWeek.every(10);
-      case "milliseconds":
+      case 'milliseconds':
         return d3.timeMillisecond.every(10);
       default:
         return d3.timeYear.every(10);
@@ -390,7 +439,7 @@ export class CdfChartD3 {
     const len = data.xs.length;
 
     for (let i = 0; i < len; i++) {
-      dt.push({ x: data.xs[i], y: data.ys[i] });
+      dt.push({ x: data.xs[i], y: data.ys[i], id: i });
     }
 
     return dt;
diff --git a/src/components/charts/DistributionPlot/distPlotReact.js b/src/components/charts/DistributionPlot/distPlotReact.js
index 8b5dd6e5..9bd9deee 100644
--- a/src/components/charts/DistributionPlot/distPlotReact.js
+++ b/src/components/charts/DistributionPlot/distPlotReact.js
@@ -14,6 +14,7 @@ function getRandomInt(min, max) {
 }
 
 /**
+ * @todo: To rename as "DistPlotReact".
  * @param props
  * @returns {*}
  * @constructor
diff --git a/src/components/charts/DistributionPlot/styles.css b/src/components/charts/DistributionPlot/styles.css
new file mode 100644
index 00000000..e47299f7
--- /dev/null
+++ b/src/components/charts/DistributionPlot/styles.css
@@ -0,0 +1,10 @@
+.lollipops-line-mouseover {
+    stroke-dasharray: 4;
+    animation: dash 2s linear infinite;
+}
+
+@keyframes dash {
+    to {
+        stroke-dashoffset: 1000;
+    }
+}