plotly · alexshoe · Feb 20, 2026 · Jan 20, 2026 · Jan 20, 2026 · Jan 28, 2026
diff --git a/src/components/legend/attributes.js b/src/components/legend/attributes.js
@@ -176,6 +176,30 @@ module.exports = {
             '*togglegroup* toggles the visibility of all items in the same legendgroup as the item clicked on the graph.'
         ].join(' ')
     },
+    titleclick: {
+        valType: 'enumerated',
+        values: ['toggle', 'toggleothers', false],
+        editType: 'legend',
+        description: [
+            'Determines the behavior on legend title click.',
+            '*toggle* toggles the visibility of all items in the legend.',
+            '*toggleothers* toggles the visibility of all other legends.',
+            '*false* disables legend title click interactions.',
+            'Defaults to *toggle* when there are multiple legends, *false* otherwise.'
+        ].join(' ')
+    },
+    titledoubleclick: {
+        valType: 'enumerated',
+        values: ['toggle', 'toggleothers', false],
+        editType: 'legend',
+        description: [
+            'Determines the behavior on legend title double-click.',
+            '*toggle* toggles the visibility of all items in the legend.',
+            '*toggleothers* toggles the visibility of all other legends.',
+            '*false* disables legend title double-click interactions.',
+            'Defaults to *toggleothers* when there are multiple legends, *false* otherwise.'
+        ].join(' ')
+    },
     x: {
         valType: 'number',
         editType: 'legend',

diff --git a/src/components/legend/defaults.js b/src/components/legend/defaults.js
@@ -9,7 +9,7 @@ var attributes = require('./attributes');
 var basePlotLayoutAttributes = require('../../plots/layout_attributes');
 var helpers = require('./helpers');
 
-function groupDefaults(legendId, layoutIn, layoutOut, fullData) {
+function groupDefaults(legendId, layoutIn, layoutOut, fullData, legendCount) {
     var containerIn = layoutIn[legendId] || {};
     var containerOut = Template.newContainer(layoutOut, legendId);
 
@@ -238,6 +238,10 @@ function groupDefaults(legendId, layoutIn, layoutOut, fullData) {
         });
 
         Lib.coerceFont(coerce, 'title.font', dfltTitleFont);
+
+        const hasMultipleLegends = legendCount > 1;
+        coerce('titleclick', hasMultipleLegends ? 'toggle' : false);
+        coerce('titledoubleclick', hasMultipleLegends ? 'toggleothers' : false);
     }
 }
 
@@ -277,7 +281,7 @@ module.exports = function legendDefaults(layoutIn, layoutOut, fullData) {
     for(i = 0; i < legends.length; i++) {
         var legendId = legends[i];
 
-        groupDefaults(legendId, layoutIn, layoutOut, allLegendsData);
+        groupDefaults(legendId, layoutIn, layoutOut, allLegendsData, legends.length);
 
         if(layoutOut[legendId]) {
             layoutOut[legendId]._id = legendId;

diff --git a/src/components/legend/draw.js b/src/components/legend/draw.js
@@ -10,7 +10,8 @@ var dragElement = require('../dragelement');
 var Drawing = require('../drawing');
 var Color = require('../color');
 var svgTextUtils = require('../../lib/svg_text_utils');
-var handleClick = require('./handle_click');
+var handleClick = require('./handle_click').handleClick;
+var handleTitleClick = require('./handle_click').handleTitleClick;
 
 var constants = require('./constants');
 var alignmentConstants = require('../../constants/alignment');
@@ -180,8 +181,14 @@ function drawOne(gd, opts) {
             .text(title.text);
 
         textLayout(titleEl, scrollBox, gd, legendObj, MAIN_TITLE); // handle mathjax or multi-line text and compute title height
+
+        // Set up title click if enabled and not in hover mode
+        if(!inHover && (legendObj.titleclick || legendObj.titledoubleclick)) {
+            setupTitleToggle(scrollBox, gd, legendObj, legendId);
+        }
     } else {
         scrollBox.selectAll('.' + legendId + 'titletext').remove();
+        scrollBox.selectAll('.' + legendId + 'titletoggle').remove();
     }
 
     var scrollBar = Lib.ensureSingle(legend, 'rect', 'scrollbar', function(s) {
@@ -198,7 +205,22 @@ function drawOne(gd, opts) {
     traces.exit().remove();
 
     traces.style('opacity', function(d) {
-        var trace = d[0].trace;
+        const legendItem = d[0];
+        const trace = legendItem.trace;
+
+        // Toggle opacity of legend group titles if all items in the group are hidden
+        if(legendItem.groupTitle) {
+            const groupName = trace.legendgroup;
+            const shapes = (fullLayout.shapes || []).filter(function(s) { return s.showlegend; });
+            const anyVisible = gd._fullData.concat(shapes).some(function(item) {
+                return item.legendgroup === groupName &&
+                    (item.legend || 'legend') === legendId &&
+                    item.visible === true;
+            });
+
+            return anyVisible ? 1 : 0.5;
+        }
+
         if(Registry.traceIs(trace, 'pie-like')) {
             return hiddenSlices.indexOf(d[0].label) !== -1 ? 0.5 : 1;
         } else {
@@ -207,7 +229,12 @@ function drawOne(gd, opts) {
     })
     .each(function() { d3.select(this).call(drawTexts, gd, legendObj); })
     .call(style, gd, legendObj)
-    .each(function() { if(!inHover) d3.select(this).call(setupTraceToggle, gd, legendId); });
+    .each(function(d) {
+        if(inHover) return;
+        // Don't create a click targets for group titles when groupclick is 'toggleitem'
+        if(d[0].groupTitle && legendObj.groupclick === 'toggleitem') return;
+        d3.select(this).call(setupTraceToggle, gd, legendId);
+    });
 
     Lib.syncOrAsync([
         Plots.previousPromises,
@@ -221,6 +248,20 @@ function drawOne(gd, opts) {
             // re-calculate title position after legend width is derived. To allow for horizontal alignment
             if(title.text) {
                 horizontalAlignTitle(titleEl, legendObj, bw);
+
+                // Position click target for the title after dimensions are computed
+                if(!inHover && (legendObj.titleclick || legendObj.titledoubleclick)) {
+                    positionTitleToggle(scrollBox, legendObj, legendId);
+                }
+
+                // Toggle opacity of legend titles if all items in the legend are hidden
+                const shapes = (fullLayout.shapes || []).filter(function(s) { return s.showlegend; });
+                const anyVisible = gd._fullData.concat(shapes).some(function(item) {
+                    const inThisLegend = (item.legend || 'legend') === legendId;
+                    return inThisLegend && item.visible === true;
+                });
+
+                titleEl.style('opacity', anyVisible ? 1 : 0.5);
             }
 
             if(!inHover) {
@@ -624,6 +665,92 @@ function setupTraceToggle(g, gd, legendId) {
     });
 }
 
+function setupTitleToggle(scrollBox, gd, legendObj, legendId) {
+    // For now, skip title click for legends containing pie-like traces
+    const hasPie = gd._fullData.some(function(trace) {
+        const legend = trace.legend || 'legend';
+        const inThisLegend = Array.isArray(legend) ? legend.includes(legendId) : legend === legendId;
+        return inThisLegend && Registry.traceIs(trace, 'pie-like');
+    });
+    if(hasPie) return;
+
+    const doubleClickDelay = gd._context.doubleClickDelay;
+    var newMouseDownTime;
+    var numClicks = 1;
+
+    const titleToggle = Lib.ensureSingle(scrollBox, 'rect', legendId + 'titletoggle', function(s) {
+        if(!gd._context.staticPlot) {
+            s.style('cursor', 'pointer').attr('pointer-events', 'all');
+        }
+        s.call(Color.fill, 'rgba(0,0,0,0)');
+    });
+
+    if(gd._context.staticPlot) return;
+
+    titleToggle.on('mousedown', function() {
+        newMouseDownTime = (new Date()).getTime();
+        if(newMouseDownTime - gd._legendMouseDownTime < doubleClickDelay) {
+            // in a click train
+            numClicks += 1;
+        } else {
+            // new click train
+            numClicks = 1;
+            gd._legendMouseDownTime = newMouseDownTime;
+        }
+    });
+    titleToggle.on('mouseup', function() {
+        if(gd._dragged || gd._editing) return;
+
+        if((new Date()).getTime() - gd._legendMouseDownTime > doubleClickDelay) {
+            numClicks = Math.max(numClicks - 1, 1);
+        }
+
+        const evtData = {
+            event: d3.event,
+            legendId: legendId,
+            data: gd.data,
+            layout: gd.layout,
+            fullData: gd._fullData,
+            fullLayout: gd._fullLayout
+        };
+
+        if(numClicks === 1 && legendObj.titleclick) {
+            const clickVal = Events.triggerHandler(gd, 'plotly_legendtitleclick', evtData);
+            if(clickVal === false) return;
+
+            legendObj._titleClickTimeout = setTimeout(function() {
+                if(gd._fullLayout) handleTitleClick(gd, legendObj, legendObj.titleclick);
+            }, doubleClickDelay);
+        } else if(numClicks === 2) {
+            if(legendObj._titleClickTimeout) clearTimeout(legendObj._titleClickTimeout);
+            gd._legendMouseDownTime = 0;
+
+            const dblClickVal = Events.triggerHandler(gd, 'plotly_legendtitledoubleclick', evtData);
+            if(dblClickVal !== false && legendObj.titledoubleclick) handleTitleClick(gd, legendObj, legendObj.titledoubleclick);
+        }
+    });
+}
+
+function positionTitleToggle(scrollBox, legendObj, legendId) {
+    const titleToggle = scrollBox.select('.' + legendId + 'titletoggle');
+    if(!titleToggle.size()) return;
+
+    const side = legendObj.title.side || 'top';
+    const bw = legendObj.borderwidth;
+    var x = bw;
+    const width = legendObj._titleWidth + 2 * constants.titlePad;
+    const height = legendObj._titleHeight + 2 * constants.titlePad;
+
+
+    if(side === 'top center') {
+        x = bw + 0.5 * (legendObj._width - 2 * bw - width);
+    } else if(side === 'top right') {
+        x = legendObj._width - bw - width;
+    }
+
+    titleToggle.attr({ x: x, y: bw, width: width, height: height });
+}
+
 function textLayout(s, g, gd, legendObj, aTitle) {
     if(legendObj._inHover) s.attr('data-notex', true); // do not process MathJax for unified hover
     svgTextUtils.convertToTspans(s, gd, function() {

diff --git a/src/components/legend/handle_click.js b/src/components/legend/handle_click.js
@@ -6,14 +6,21 @@ var pushUnique = Lib.pushUnique;
 
 var SHOWISOLATETIP = true;
 
-module.exports = function handleClick(g, gd, numClicks) {
+exports.handleClick = function handleClick(g, gd, numClicks) {
     var fullLayout = gd._fullLayout;
 
     if(gd._dragged || gd._editing) return;
 
-    var itemClick = fullLayout.legend.itemclick;
-    var itemDoubleClick = fullLayout.legend.itemdoubleclick;
-    var groupClick = fullLayout.legend.groupclick;
+
+    const legendItem = g.data()[0][0];
+    if(legendItem.groupTitle && legendItem.noClick) return;
+
+    const legendId = legendItem.trace.legend || 'legend';
+    const legendObj = fullLayout[legendId];
+
+    const itemClick = legendObj.itemclick;
+    const itemDoubleClick = legendObj.itemdoubleclick;
+    const groupClick = legendObj.groupclick;
 
     if(numClicks === 1 && itemClick === 'toggle' && itemDoubleClick === 'toggleothers' &&
         SHOWISOLATETIP && gd.data && gd._context.showTips
@@ -35,9 +42,6 @@ module.exports = function handleClick(g, gd, numClicks) {
         fullLayout.hiddenlabels.slice() :
         [];
 
-    var legendItem = g.data()[0][0];
-    if(legendItem.groupTitle && legendItem.noClick) return;
-
     var fullData = gd._fullData;
     var shapesWithLegend = (fullLayout.shapes || []).filter(function(d) { return d.showlegend; });
     var allLegendItems = fullData.concat(shapesWithLegend);
@@ -269,3 +273,64 @@ module.exports = function handleClick(g, gd, numClicks) {
         }
     }
 };
+
+exports.handleTitleClick = function handleTitleClick(gd, legendObj, mode) {
+    const fullLayout = gd._fullLayout;
+    const fullData = gd._fullData;
+    const legendId = legendObj._id || 'legend';
+    const shapesWithLegend = (fullLayout.shapes || []).filter(function(d) { return d.showlegend; });
+    const allLegendItems = fullData.concat(shapesWithLegend);
+
+    function isInLegend(item) {
+        return (item.legend || 'legend') === legendId;
+    }
+
+    var toggleThisLegend;
+    var toggleOtherLegends;
+
+    if(mode === 'toggle') {
+        // If any item is visible in this legend, hide all. If all are hidden, show all
+        const anyVisibleHere = allLegendItems.some(function(item) {
+            return isInLegend(item) && item.visible === true;
+        });
+
+        toggleThisLegend = !anyVisibleHere;
+        toggleOtherLegends = null;
+    } else {
+        // isolate this legend or set all legends to visible
+        const anyVisibleElsewhere = allLegendItems.some(function(item) {
+            return !isInLegend(item) && item.visible === true && item.showlegend !== false;
+        });
+
+        toggleThisLegend = true;
+        toggleOtherLegends = !anyVisibleElsewhere;
+    }
+
+    const dataUpdate = { visible: [] };
+    const dataIndices = [];
+    const updatedShapes = (fullLayout.shapes || []).map(function(d) { return d._input; });
+    var shapesUpdated = false;
+
+    for(var i = 0; i < allLegendItems.length; i++) {
+        const item = allLegendItems[i];
+        const shouldShow = isInLegend(item) ? toggleThisLegend : toggleOtherLegends;
+        const newVis = shouldShow ? true : 'legendonly';
+
+        // Only update if the item is visible and the visibility is different from the new visibility
+        if ((item.visible !== false) && (shouldShow !== null) && (item.visible !== newVis)) {
+            if(item._isShape) {
+                updatedShapes[item._index].visible = newVis;
+                shapesUpdated = true;
+            } else {
+                dataIndices.push(item.index);
+                dataUpdate.visible.push(newVis);
+            }
+        }
+    }
+
+    if(shapesUpdated) {
+        Registry.call('_guiUpdate', gd, dataUpdate, {shapes: updatedShapes}, dataIndices);
+    } else if(dataIndices.length) {
+        Registry.call('_guiRestyle', gd, dataUpdate, dataIndices);
+    }
+};