From d3c8c41fc401286a5080753677059f602d2013ec Mon Sep 17 00:00:00 2001
From: colinl <clanlaw@gmail.com>
Date: Sun, 22 Mar 2026 10:42:45 +0000
Subject: [PATCH 1/3] Fix filtering of multi series messages

---
 nodes/widgets/ui_chart.js | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/nodes/widgets/ui_chart.js b/nodes/widgets/ui_chart.js
index 6930f5cf3..fa8c64ca3 100644
--- a/nodes/widgets/ui_chart.js
+++ b/nodes/widgets/ui_chart.js
@@ -63,10 +63,12 @@ module.exports = function (RED) {
                 const ago = (removeOlder * removeOlderUnit) * 1000 // milliseconds ago
                 const cutOff = (new Date()).getTime() - ago
                 const filterFn = (msg) => {
-                    let timestamp = msg._datapoint.x
+                    // msg._datapoint may be a single point or, in the case of multiple series in one msg, an array
+                    // if it is an array then all the elements will have the same timestamp so use the first one
+                    let timestamp = Array.isArray(msg._datapoint) ? msg._datapoint[0].x : msg._datapoint.x
                     // is x already a millisecond timestamp?
-                    if (typeof (msg._datapoint.x) === 'string') {
-                        timestamp = (new Date(msg._datapoint.x)).getTime()
+                    if (typeof (timestamp) === 'string') {
+                        timestamp = (new Date(timestamp)).getTime()
                     }
                     return timestamp > cutOff
                 }

From 2e3654cbe50f91122f09039b7adaec63d3718953 Mon Sep 17 00:00:00 2001
From: colinl <clanlaw@gmail.com>
Date: Sun, 22 Mar 2026 11:35:26 +0000
Subject: [PATCH 2/3] Fix client side loading of history of multi series
 messages

---
 ui/src/widgets/ui-chart/UIChart.vue | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/ui/src/widgets/ui-chart/UIChart.vue b/ui/src/widgets/ui-chart/UIChart.vue
index 71beec29e..6ca7ac2b2 100644
--- a/ui/src/widgets/ui-chart/UIChart.vue
+++ b/ui/src/widgets/ui-chart/UIChart.vue
@@ -396,6 +396,7 @@ export default {
             return value
         },
         onLoad (history) {
+
             if (history && history.length > 0) {
                 // we have received a history of data points
                 // we need to add them to the chart
@@ -509,13 +510,8 @@ export default {
             // determine what type of msg we have
             if (Array.isArray(msg) && msg.length > 0) {
                 // we have received an array of messages (loading from stored history)
-                msg.forEach((m, i) => {
-                    const p = m.payload
-                    const d = m._datapoint // server-side we compute a chart friendly format
-                    const label = d.category
-                    if (label !== null && label !== undefined) {
-                        this.addPoints(p, d, label, options)
-                    }
+                msg.forEach((m) => {
+                    this.add(m)
                 })
             } else if (Array.isArray(payload) && msg.payload.length > 0) {
                 // we have received a message with an array of data points

From cfda6c97c09a3556c78fe79a269dc8db5b7b6f0d Mon Sep 17 00:00:00 2001
From: colinl <clanlaw@gmail.com>
Date: Sun, 22 Mar 2026 11:50:10 +0000
Subject: [PATCH 3/3] Linter error fix

---
 ui/src/widgets/ui-chart/UIChart.vue | 1 -
 1 file changed, 1 deletion(-)

diff --git a/ui/src/widgets/ui-chart/UIChart.vue b/ui/src/widgets/ui-chart/UIChart.vue
index 6ca7ac2b2..a730cbe7f 100644
--- a/ui/src/widgets/ui-chart/UIChart.vue
+++ b/ui/src/widgets/ui-chart/UIChart.vue
@@ -396,7 +396,6 @@ export default {
             return value
         },
         onLoad (history) {
-
             if (history && history.length > 0) {
                 // we have received a history of data points
                 // we need to add them to the chart