fix: pending drag effect calls stale handleSectionItemDragStart

The useEffect with [] deps captured handleSectionItemDragStart
from initial render, which read an empty selectedItemIds.
Added handleSectionItemDragStartRef that stays current across
renders; the effect calls ref.current instead of the closure.

app/static/js/app.jsx

@@ -6948,6 +6948,7 @@ const App = () => {
   const sweepTrackIdRef = useRef(null);
   const sweepSelectRef = useRef(null);
   const pendingDragRef = useRef(null); // { trackId, itemType, itemId, clickOffset, startX, startY }
+  const handleSectionItemDragStartRef = useRef(null);
   const [localSelectionTrackId, setLocalSelectionTrackId] = useState(null);
   const [localSelectionStart, setLocalSelectionStart] = useState(null);
   const [localSelectionEnd, setLocalSelectionEnd] = useState(null);
@@ -11758,6 +11759,7 @@ const App = () => {
     }
     setDraggedSectionItem({ trackId, itemType, itemId, clickOffset, multiIds });
   };
+  handleSectionItemDragStartRef.current = handleSectionItemDragStart;
 
   // ── Section / MIDI Item Resize Start ──
   const handleSectionItemResizeStart = (trackId, itemType, itemId, side, clickTime) => {
@@ -11875,7 +11877,7 @@ const App = () => {
       var dx = e.clientX - pd.startX;
       if (Math.abs(dx) > 5) {
         pendingDragRef.current = null;
-        handleSectionItemDragStart(pd.trackId, pd.itemType, pd.itemId, pd.clickOffset, true);
+        if (handleSectionItemDragStartRef.current) handleSectionItemDragStartRef.current(pd.trackId, pd.itemType, pd.itemId, pd.clickOffset, true);
       }
     };
     document.addEventListener('mousemove', handleMouseMove);

app/static/js/app.precompiled.js

@@ -193,7 +193,7 @@ const[snapValue,setSnapValue]=useState('free');// 'free', '1', '1/2', '1/4', '1/
 const snapTime=(time,snapVal,bpmVal)=>{if(snapVal==='free')return time;const beatDuration=60/parseFloat(bpmVal||120);let divisor=1;if(snapVal==='4')divisor=4;else if(snapVal==='1')divisor=1;else if(snapVal==='1/2')divisor=0.5;else if(snapVal==='1/4')divisor=0.25;else if(snapVal==='1/8')divisor=0.125;else if(snapVal==='1/16')divisor=0.0625;else if(snapVal==='1/32')divisor=0.03125;const gridSpacing=beatDuration*divisor;return Math.round(time/gridSpacing)*gridSpacing;};const snapValueRef=useRef(snapValue);snapValueRef.current=snapValue;const bpmRef=useRef(bpm);bpmRef.current=bpm;// BMP for Tempo Track - LOOP_EDITOR_2.md §6
 const[selectedTrackId,setSelectedTrackId]=useState('1');const[selectedItemIds,setSelectedItemIds]=useState(new Set());const[currentTime,setCurrentTime]=useState(0);const[isPlaying,setIsPlaying]=useState(false);const[selectionStart,setSelectionStart]=useState(null);const[selectionEnd,setSelectionEnd]=useState(null);const[selectionFollowsTempo,setSelectionFollowsTempo]=useState(true);const selectionRef=useRef({start:null,end:null});selectionRef.current={start:selectionStart,end:selectionEnd};const[selectionMode,setSelectionMode]=useState(null);// 'global' (from ruler) | 'local' (from track)
 const[sweepSelect,setSweepSelect]=useState(null);const isSweepingRef=useRef(false);const sweepStartRef=useRef(0);const sweepTrackIdRef=useRef(null);const sweepSelectRef=useRef(null);const pendingDragRef=useRef(null);// { trackId, itemType, itemId, clickOffset, startX, startY }
-const[localSelectionTrackId,setLocalSelectionTrackId]=useState(null);const[localSelectionStart,setLocalSelectionStart]=useState(null);const[localSelectionEnd,setLocalSelectionEnd]=useState(null);const[zoom,setZoom]=useState(100);const[isLoopingSelection,setIsLoopingSelection]=useState(false);const[beginBar,setBeginBar]=useState(0);const[endBar,setEndBar]=useState(0);const[numberBar,setNumberBar]=useState(1);const[subTabHeight,setSubTabHeight]=useState(96);const[isExporting,setIsExporting]=useState(false);const[projectName,setProjectName]=useState(()=>localStorage.getItem('sonic_project_name')||'');const[currentProjectId,setCurrentProjectId]=useState(()=>localStorage.getItem('sonic_project_id')||null);const[saveProjectModalOpen,setSaveProjectModalOpen]=useState(false);const[saveAsModalOpen,setSaveAsModalOpen]=useState(false);const soloedTrack=tracks.find(t=>t.solo);const soloedTrackId=soloedTrack?soloedTrack.id:null;const[toastMessage,setToastMessage]=useState(null);const[audioDevices,setAudioDevices]=useState([]);const[midiDevices,setMidiDevices]=useState([]);const[selectedMidiInputId,setSelectedMidiInputId]=useState('');const handleMidiInputSelect=id=>{setSelectedMidiInputId(id);if(window.SonicRecorderManager){window.SonicRecorderManager.setSelectedMidiInputId(id);}};useEffect(()=>{if(navigator.mediaDevices&&navigator.mediaDevices.enumerateDevices){navigator.mediaDevices.enumerateDevices().then(devices=>{setAudioDevices(devices.filter(d=>d.kind==='audioinput'));}).catch(err=>console.log('Enumerate audio devices error:',err));}if(navigator.requestMIDIAccess){navigator.requestMIDIAccess().then(access=>{const inputs=[];for(let input of access.inputs.values()){inputs.push(input);input.onmidimessage=msg=>{console.log(`[DevLog] [Raw MIDI] Received from "${input.name}" (ID: ${input.id}) - Data:`,Array.from(msg.data));if(msg.data.length<3)return;const cmd=msg.data[0]>>4;const pitch=msg.data[1];const velocity=msg.data[2];if(cmd===0x9&&velocity>0){lastMidiNoteRef.current={pitch,velocity,startTime:performance.now(),length:0};setLastMidiNote({pitch,velocity,length:0,time:Date.now()});activeMidiPitchesRef.current.add(pitch);setActiveMidiPitches(new Set(activeMidiPitchesRef.current));// Route MIDI input to ALL armed tracks on their dedicated channels
+const handleSectionItemDragStartRef=useRef(null);const[localSelectionTrackId,setLocalSelectionTrackId]=useState(null);const[localSelectionStart,setLocalSelectionStart]=useState(null);const[localSelectionEnd,setLocalSelectionEnd]=useState(null);const[zoom,setZoom]=useState(100);const[isLoopingSelection,setIsLoopingSelection]=useState(false);const[beginBar,setBeginBar]=useState(0);const[endBar,setEndBar]=useState(0);const[numberBar,setNumberBar]=useState(1);const[subTabHeight,setSubTabHeight]=useState(96);const[isExporting,setIsExporting]=useState(false);const[projectName,setProjectName]=useState(()=>localStorage.getItem('sonic_project_name')||'');const[currentProjectId,setCurrentProjectId]=useState(()=>localStorage.getItem('sonic_project_id')||null);const[saveProjectModalOpen,setSaveProjectModalOpen]=useState(false);const[saveAsModalOpen,setSaveAsModalOpen]=useState(false);const soloedTrack=tracks.find(t=>t.solo);const soloedTrackId=soloedTrack?soloedTrack.id:null;const[toastMessage,setToastMessage]=useState(null);const[audioDevices,setAudioDevices]=useState([]);const[midiDevices,setMidiDevices]=useState([]);const[selectedMidiInputId,setSelectedMidiInputId]=useState('');const handleMidiInputSelect=id=>{setSelectedMidiInputId(id);if(window.SonicRecorderManager){window.SonicRecorderManager.setSelectedMidiInputId(id);}};useEffect(()=>{if(navigator.mediaDevices&&navigator.mediaDevices.enumerateDevices){navigator.mediaDevices.enumerateDevices().then(devices=>{setAudioDevices(devices.filter(d=>d.kind==='audioinput'));}).catch(err=>console.log('Enumerate audio devices error:',err));}if(navigator.requestMIDIAccess){navigator.requestMIDIAccess().then(access=>{const inputs=[];for(let input of access.inputs.values()){inputs.push(input);input.onmidimessage=msg=>{console.log(`[DevLog] [Raw MIDI] Received from "${input.name}" (ID: ${input.id}) - Data:`,Array.from(msg.data));if(msg.data.length<3)return;const cmd=msg.data[0]>>4;const pitch=msg.data[1];const velocity=msg.data[2];if(cmd===0x9&&velocity>0){lastMidiNoteRef.current={pitch,velocity,startTime:performance.now(),length:0};setLastMidiNote({pitch,velocity,length:0,time:Date.now()});activeMidiPitchesRef.current.add(pitch);setActiveMidiPitches(new Set(activeMidiPitchesRef.current));// Route MIDI input to ALL armed tracks on their dedicated channels
 // Do NOT use raw MIDI hardware channel (msg.data[0] & 0x0F)
 if(window.SonicSF){var allTracks=activeTracksRef.current||[];var arSubs=subTabsRef&&subTabsRef.current?subTabsRef.current.filter(function(s){return s.type==='PIANO_ROLL'&&s.isArmed;}):[];var armedTracks=allTracks.filter(function(t){return t.isArmed;});// Piano Roll arming has priority: route to each armed sub-tab's parent track
 if(arSubs.length>0){arSubs.forEach(function(as){var asTrk=allTracks.find(function(t){return t.id===as.trackId;});var asCh=window.SonicPianoRoll?window.SonicPianoRoll.getTrackMidiChannel(asTrk,allTracks):asTrk?asTrk.midiChannel:0;var asProg=as.instrumentProgram;var asSe=as.synth_engine;window.SonicSF.playNote(pitch,velocity,60000,undefined,asProg,null,asCh,asSe);});}// Route to ALL armed tracks (not just the first one)
@@ -332,10 +332,10 @@ useEffect(()=>{const handleMouseMove=e=>{const stretch=stretchedClipRef.current;
 const handleDeselectItem=itemId=>{setSelectedItemIds(prev=>{var next=new Set(prev);next.delete(itemId);return next;});};// ── Add item to selectedItemIds ──
 const handleAddToSelection=itemId=>{setSelectedItemIds(prev=>{var next=new Set(prev);next.add(itemId);return next;});};const handleSetPendingDrag=(trackId,itemType,itemId,clickOffset,e)=>{pendingDragRef.current={trackId,itemType,itemId,clickOffset,startX:e.clientX,startY:e.clientY};};// ── Sweep Select ──
 const handleSweepSelectStart=(trackId,startTime)=>{isSweepingRef.current=true;sweepStartRef.current=startTime;sweepTrackIdRef.current=trackId;var init={startTime,endTime:startTime};sweepSelectRef.current=init;setSweepSelect(init);setSelectedItemIds(new Set());};// ── Section / MIDI Item Drag Start ──
-const handleSectionItemDragStart=(trackId,itemType,itemId,clickOffset,isDuplicate)=>{var curTracks=activeTracksRef.current||activeTracks;var multiIds=null;if(selectedItemIds&&selectedItemIds.size>0&&selectedItemIds.has(itemId)){var selArr=Array.from(selectedItemIds);var originals={};curTracks.forEach(function(t){(t.sections||[]).forEach(function(s){if(selArr.indexOf(s.id)>=0)originals[s.id]={type:'section',start:s.start};});(t.midiItems||[]).forEach(function(m){if(selArr.indexOf(m.id)>=0)originals[m.id]={type:'midiItem',start:m.startTime};});(t.clips||[]).forEach(function(c){var cid=c.id==='default'?'default_'+t.id:c.id;if(selArr.indexOf(cid)>=0)originals[cid]={type:'clip',start:c.startTime};});});if(Object.keys(originals).length>0)multiIds=originals;}if(isDuplicate){var track=curTracks.find(function(t){return t.id===trackId;});if(!track)return;if(multiIds){var newOriginals={};updateActiveTracks(function(prev){return prev.map(function(t){var updatedSections=t.sections?t.sections.slice():[];var updatedMidi=t.midiItems?t.midiItems.slice():[];var updatedClips=t.clips?t.clips.slice():[];Object.keys(multiIds).forEach(function(oid){var info=multiIds[oid];if(info.type==='section'){var sec=(t.sections||[]).find(function(s){return s.id===oid;});if(sec){var newId='sec_dup_'+Date.now()+'_'+Math.random().toString(36).substr(2,5);updatedSections.push({...sec,id:newId,name:sec.name+' (Copy)'});newOriginals[newId]={type:'section',start:sec.start};}}else if(info.type==='midiItem'){var mid=(t.midiItems||[]).find(function(m){return m.id===oid;});if(mid){var newId='midi_dup_'+Date.now()+'_'+Math.random().toString(36).substr(2,5);updatedMidi.push({...mid,id:newId,name:mid.name+' (Copy)'});newOriginals[newId]={type:'midiItem',start:mid.startTime};}}else if(info.type==='clip'){var clip=(t.clips||[]).find(function(c){return c.id===oid||'default_'+t.id===oid;});if(clip){var newId='clip_dup_'+Date.now()+'_'+Math.random().toString(36).substr(2,5);updatedClips.push({...clip,id:newId,startTime:clip.startTime,name:clip.name+' (Copy)'});newOriginals[newId]={type:'clip',start:clip.startTime};}}});var changed=t.sections&&t.sections.length!==updatedSections.length;return t.id===trackId?{...t,sections:updatedSections,midiItems:updatedMidi,clips:updatedClips}:t;});});setDraggedSectionItem({trackId,itemType,itemId,clickOffset,multiIds:newOriginals});}else{var items=itemType==='section'?track.sections||[]:track.midiItems||[];var item=items.find(function(it){return it.id===itemId;});if(!item)return;var newId=itemType+'_dup_'+Date.now();var newItem={...item,id:newId,name:item.name+' (Copy)'};updateActiveTracks(function(prev){return prev.map(function(t){if(t.id!==trackId)return t;var updated=itemType==='section'?[...(t.sections||[]),newItem]:[...(t.midiItems||[]),newItem];return itemType==='section'?{...t,sections:updated}:{...t,midiItems:updated};});});setDraggedSectionItem({trackId,itemType,itemId:newId,clickOffset,isDuplicate:false});}return;}setDraggedSectionItem({trackId,itemType,itemId,clickOffset,multiIds});};// ── Section / MIDI Item Resize Start ──
+const handleSectionItemDragStart=(trackId,itemType,itemId,clickOffset,isDuplicate)=>{var curTracks=activeTracksRef.current||activeTracks;var multiIds=null;if(selectedItemIds&&selectedItemIds.size>0&&selectedItemIds.has(itemId)){var selArr=Array.from(selectedItemIds);var originals={};curTracks.forEach(function(t){(t.sections||[]).forEach(function(s){if(selArr.indexOf(s.id)>=0)originals[s.id]={type:'section',start:s.start};});(t.midiItems||[]).forEach(function(m){if(selArr.indexOf(m.id)>=0)originals[m.id]={type:'midiItem',start:m.startTime};});(t.clips||[]).forEach(function(c){var cid=c.id==='default'?'default_'+t.id:c.id;if(selArr.indexOf(cid)>=0)originals[cid]={type:'clip',start:c.startTime};});});if(Object.keys(originals).length>0)multiIds=originals;}if(isDuplicate){var track=curTracks.find(function(t){return t.id===trackId;});if(!track)return;if(multiIds){var newOriginals={};updateActiveTracks(function(prev){return prev.map(function(t){var updatedSections=t.sections?t.sections.slice():[];var updatedMidi=t.midiItems?t.midiItems.slice():[];var updatedClips=t.clips?t.clips.slice():[];Object.keys(multiIds).forEach(function(oid){var info=multiIds[oid];if(info.type==='section'){var sec=(t.sections||[]).find(function(s){return s.id===oid;});if(sec){var newId='sec_dup_'+Date.now()+'_'+Math.random().toString(36).substr(2,5);updatedSections.push({...sec,id:newId,name:sec.name+' (Copy)'});newOriginals[newId]={type:'section',start:sec.start};}}else if(info.type==='midiItem'){var mid=(t.midiItems||[]).find(function(m){return m.id===oid;});if(mid){var newId='midi_dup_'+Date.now()+'_'+Math.random().toString(36).substr(2,5);updatedMidi.push({...mid,id:newId,name:mid.name+' (Copy)'});newOriginals[newId]={type:'midiItem',start:mid.startTime};}}else if(info.type==='clip'){var clip=(t.clips||[]).find(function(c){return c.id===oid||'default_'+t.id===oid;});if(clip){var newId='clip_dup_'+Date.now()+'_'+Math.random().toString(36).substr(2,5);updatedClips.push({...clip,id:newId,startTime:clip.startTime,name:clip.name+' (Copy)'});newOriginals[newId]={type:'clip',start:clip.startTime};}}});var changed=t.sections&&t.sections.length!==updatedSections.length;return t.id===trackId?{...t,sections:updatedSections,midiItems:updatedMidi,clips:updatedClips}:t;});});setDraggedSectionItem({trackId,itemType,itemId,clickOffset,multiIds:newOriginals});}else{var items=itemType==='section'?track.sections||[]:track.midiItems||[];var item=items.find(function(it){return it.id===itemId;});if(!item)return;var newId=itemType+'_dup_'+Date.now();var newItem={...item,id:newId,name:item.name+' (Copy)'};updateActiveTracks(function(prev){return prev.map(function(t){if(t.id!==trackId)return t;var updated=itemType==='section'?[...(t.sections||[]),newItem]:[...(t.midiItems||[]),newItem];return itemType==='section'?{...t,sections:updated}:{...t,midiItems:updated};});});setDraggedSectionItem({trackId,itemType,itemId:newId,clickOffset,isDuplicate:false});}return;}setDraggedSectionItem({trackId,itemType,itemId,clickOffset,multiIds});};handleSectionItemDragStartRef.current=handleSectionItemDragStart;// ── Section / MIDI Item Resize Start ──
 const handleSectionItemResizeStart=(trackId,itemType,itemId,side,clickTime)=>{const curTracks=activeTracks;const track=curTracks.find(t=>t.id===trackId);if(!track)return;const items=itemType==='section'?track.sections:track.midiItems;const item=(items||[]).find(it=>it.id===itemId);if(!item)return;const start=itemType==='section'?item.start:item.startTime;setResizedSectionItem({trackId,itemType,itemId,side,originalStart:start,originalDuration:item.duration});};// ── Document-level mousemove/mouseup for Section/MIDI item drag ──
 useEffect(()=>{const handleMouseMove=e=>{const drag=draggedSectionItemRef.current;if(!drag)return;const wrapper=timelineWrapperRef.current;if(!wrapper)return;autoScrollTimeline(e.clientX);const rect=wrapper.getBoundingClientRect();const scrollLeft=wrapper.scrollLeft;const mouseX=e.clientX-rect.left+scrollLeft;const time=Math.max(0,mouseX/zoom-leadInMarginRef.current);const beatSec=60.0/(parseInt(bpm)||120);const secondsPerBar=beatSec*4;const marginBar=maxDurationRef.current-secondsPerBar;const rawStart=Math.max(0,Math.min(time-drag.clickOffset,marginBar));const newStart=snapTime(rawStart,snapValueRef.current,bpmRef.current);const itemPx=newStart*zoom;const keepMargin=80;if(itemPx>scrollLeft+rect.width-keepMargin){wrapper.scrollLeft=itemPx-rect.width+keepMargin;setCanvasRedrawCount(n=>n+1);}else if(itemPx<scrollLeft+keepMargin){wrapper.scrollLeft=Math.max(0,itemPx-keepMargin);setCanvasRedrawCount(n=>n+1);}const targetTrackId=hoveredTrackIdRef.current||drag.trackId;updateActiveTracks(prev=>{let movedItem=null;for(let track of prev){const items=drag.itemType==='section'?track.sections||[]:track.midiItems||[];const found=items.find(it=>it.id===drag.itemId);if(found){movedItem=found;break;}}return prev.map(t=>{if(drag.multiIds){var dragOrigStart=drag.multiIds[drag.itemId]?drag.multiIds[drag.itemId].start:0;var delta=newStart-dragOrigStart;var midSections=(t.sections||[]).slice();var midMidis=(t.midiItems||[]).slice();Object.keys(drag.multiIds).forEach(function(mid){var info=drag.multiIds[mid];var newVal=info.start+delta;if(info.type==='section'){var idx=midSections.findIndex(function(s){return s.id===mid;});if(idx>=0)midSections[idx]={...midSections[idx],start:Math.max(0,newVal)};}else if(info.type==='midiItem'){var idx=midMidis.findIndex(function(m){return m.id===mid;});if(idx>=0)midMidis[idx]={...midMidis[idx],startTime:Math.max(0,newVal)};}});return t.id===targetTrackId?{...t,sections:midSections,midiItems:midMidis}:{...t,sections:t.id===drag.trackId?midSections:t.sections,midiItems:t.id===drag.trackId?midMidis:t.midiItems};}const items=drag.itemType==='section'?t.sections||[]:t.midiItems||[];const updatedItems=items.filter(it=>it.id!==drag.itemId);if(t.id===targetTrackId){if(movedItem){updatedItems.push(drag.itemType==='section'?{...movedItem,start:newStart}:{...movedItem,startTime:newStart});}else{if(drag.itemType==='section'){updatedItems.push({id:drag.itemId,name:'Section',start:newStart,duration:4*secondsPerBar,color:'#06b6d4'});}else{updatedItems.push({id:drag.itemId,name:'MIDI Item',startTime:newStart,duration:4*secondsPerBar,notes:[],color:'#a78bfa'});}}}return drag.itemType==='section'?{...t,sections:updatedItems}:{...t,midiItems:updatedItems};});});if(drag.trackId!==targetTrackId){setDraggedSectionItem(prev=>({...prev,trackId:targetTrackId}));}};const handleMouseUp=()=>{const drag=draggedSectionItemRef.current;if(!drag)return;setDraggedSectionItem(null);showToast(`Đã di chuyển ${drag.itemType==='section'?'section':'MIDI item'}.`,'success');};document.addEventListener('mousemove',handleMouseMove);document.addEventListener('mouseup',handleMouseUp);return()=>{document.removeEventListener('mousemove',handleMouseMove);document.removeEventListener('mouseup',handleMouseUp);};},[zoom,activeTab,sessionTabs]);// ── Pending drag: Ctrl+click toggles selection; mousemove > threshold starts copy-drag ──
-useEffect(()=>{const handleMouseMove=e=>{var pd=pendingDragRef.current;if(!pd)return;var dx=e.clientX-pd.startX;if(Math.abs(dx)>5){pendingDragRef.current=null;handleSectionItemDragStart(pd.trackId,pd.itemType,pd.itemId,pd.clickOffset,true);}};document.addEventListener('mousemove',handleMouseMove);var handleMouseUp=function(){pendingDragRef.current=null;};document.addEventListener('mouseup',handleMouseUp);return function(){document.removeEventListener('mousemove',handleMouseMove);document.removeEventListener('mouseup',handleMouseUp);pendingDragRef.current=null;};},[]);// ── Document-level mousemove/mouseup for Section/MIDI item resize ──
+useEffect(()=>{const handleMouseMove=e=>{var pd=pendingDragRef.current;if(!pd)return;var dx=e.clientX-pd.startX;if(Math.abs(dx)>5){pendingDragRef.current=null;if(handleSectionItemDragStartRef.current)handleSectionItemDragStartRef.current(pd.trackId,pd.itemType,pd.itemId,pd.clickOffset,true);}};document.addEventListener('mousemove',handleMouseMove);var handleMouseUp=function(){pendingDragRef.current=null;};document.addEventListener('mouseup',handleMouseUp);return function(){document.removeEventListener('mousemove',handleMouseMove);document.removeEventListener('mouseup',handleMouseUp);pendingDragRef.current=null;};},[]);// ── Document-level mousemove/mouseup for Section/MIDI item resize ──
 useEffect(()=>{const handleMouseMove=e=>{const resize=resizedSectionItemRef.current;if(!resize)return;const wrapper=timelineWrapperRef.current;if(!wrapper)return;autoScrollTimeline(e.clientX);const rect=wrapper.getBoundingClientRect();const scrollLeft=wrapper.scrollLeft;const mouseX=e.clientX-rect.left+scrollLeft;const time=Math.max(0,mouseX/zoom-leadInMarginRef.current);updateActiveTracks(prev=>prev.map(t=>{if(t.id!==resize.trackId)return t;const items=resize.itemType==='section'?[...(t.sections||[])]:[...(t.midiItems||[])];const idx=items.findIndex(it=>it.id===resize.itemId);if(idx===-1)return t;const item=items[idx];if(resize.side==='left'){const beatSec=60.0/(parseInt(bpm)||120);const newStart=Math.max(0,Math.min(time,resize.originalStart+resize.originalDuration-0.1));const end=resize.originalStart+resize.originalDuration;const newDuration=end-newStart;if(newDuration<0.1)return t;items[idx]=resize.itemType==='section'?{...item,start:newStart,duration:newDuration}:{...item,startTime:newStart,duration:newDuration};}else{const secondsPerBar=60.0/(parseInt(bpm)||120)*4;const marginBar=maxDurationRef.current-secondsPerBar;const clampedTime=Math.min(time,marginBar);const snappedDuration=snapValueRef.current!=='free'?snapTime(clampedTime-resize.originalStart,snapValueRef.current,bpm):clampedTime-resize.originalStart;const newDuration=Math.max(0.1,snappedDuration);items[idx]={...item,duration:newDuration};}return resize.itemType==='section'?{...t,sections:items}:{...t,midiItems:items};}));setCanvasRedrawCount(n=>n+1);const edgePx=(resize.side==='left'?Math.max(0,time):time)*zoom;const keepMargin=80;if(edgePx>scrollLeft+rect.width-keepMargin){wrapper.scrollLeft=edgePx-rect.width+keepMargin;setCanvasRedrawCount(n=>n+1);}else if(edgePx<scrollLeft+keepMargin){wrapper.scrollLeft=Math.max(0,edgePx-keepMargin);setCanvasRedrawCount(n=>n+1);}};const handleMouseUp=()=>{const resize=resizedSectionItemRef.current;if(!resize)return;setResizedSectionItem(null);};document.addEventListener('mousemove',handleMouseMove);document.addEventListener('mouseup',handleMouseUp);return()=>{document.removeEventListener('mousemove',handleMouseMove);document.removeEventListener('mouseup',handleMouseUp);};},[zoom,activeTab,sessionTabs]);// ── Sweep Select mousemove/mouseup ──
 useEffect(()=>{const handleMouseMove=e=>{if(!isSweepingRef.current)return;const wrapper=timelineWrapperRef.current;if(!wrapper)return;const rect=wrapper.getBoundingClientRect();const scrollLeft=wrapper.scrollLeft;const mouseX=e.clientX-rect.left+scrollLeft;const time=Math.max(0,mouseX/zoom-leadInMarginRef.current);setSweepSelect(prev=>{var updated=prev?{...prev,endTime:time}:null;sweepSelectRef.current=updated;return updated;});};const handleMouseUp=()=>{if(!isSweepingRef.current)return;isSweepingRef.current=false;sweepTrackIdRef.current=null;const sweep=sweepSelectRef.current;sweepSelectRef.current=null;if(sweep){const start=Math.min(sweep.startTime,sweep.endTime);const end=Math.max(sweep.startTime,sweep.endTime);const curTracks=activeTracksRef.current||[];const found=new Set();curTracks.forEach(t=>{(t.midiItems||[]).forEach(m=>{if(m.startTime<end&&m.startTime+m.duration>start){found.add(m.id);}});(t.sections||[]).forEach(s=>{if(s.start<end&&s.start+s.duration>start){found.add(s.id);}});(t.clips||[]).forEach(c=>{const dur=c.buffer?c.buffer.duration/(c.speed||1.0):4;if(c.startTime<end&&c.startTime+dur>start){const cid=c.id==='default'?'default_'+t.id:c.id;found.add(cid);}});});setSelectedItemIds(found);setSweepSelect(null);sweepTrackIdRef.current=null;}};document.addEventListener('mousemove',handleMouseMove);document.addEventListener('mouseup',handleMouseUp);return()=>{document.removeEventListener('mousemove',handleMouseMove);document.removeEventListener('mouseup',handleMouseUp);};},[zoom]);const handleSelectRange=(start,end,reset)=>{const maxLen=maxDuration;const cleanStart=Math.max(0,Math.min(maxLen,start));const cleanEnd=Math.max(0,Math.min(maxLen,end));if(reset){setSelectionStart(cleanStart);setSelectionEnd(cleanEnd);}else{setSelectionEnd(cleanEnd);}// LOOP_EDITOR_2.md §4.2: new selection = enable looping
 setSelectionCleared(false);};const handleSelectionInputChange=(field,val)=>{const numericVal=Math.max(0,parseFloat(val)||0);if(selectionMode==='local'){// Editing local selection directly