diff --git a/app/static/js/app.jsx b/app/static/js/app.jsx
index 234ae17..1e6a5a6 100644
--- a/app/static/js/app.jsx
+++ b/app/static/js/app.jsx
@@ -7383,7 +7383,43 @@ const App = () => {
       }
       if (ctrl && !alt && e.key === 's') {
         e.preventDefault();
-        handleSaveProject();
+        const curTab = activeTabRef.current;
+        if (curTab === 'main') {
+          // Main session: save project + save all dirty sub-tabs
+          handleSaveProject();
+          subTabsRef.current.filter(s => s.isDirty).forEach(st => {
+            if (st.type === 'PIANO_ROLL') {
+              handleSaveMidiNotes(st.id, st.trackId, st.target_id, st.notes || []);
+            } else if (st.type === 'SECTION') {
+              handleSaveSectionTab(st.id);
+            } else if (st.buffer) {
+              // Audio clip sub-tab: save buffer to track
+              const subTrack = activeTracksRef.current.find(t => t.id === st.trackId);
+              if (subTrack) {
+                updateActiveTracks(prev => prev.map(t => t.id === st.trackId ? { ...t, buffer: st.buffer } : t));
+              }
+            }
+            showToast('Đã lưu', 'success');
+          });
+        } else {
+          // Sub-tab: save current tab
+          const st = subTabsRef.current.find(s => s.id === curTab);
+          if (st) {
+            if (st.type === 'PIANO_ROLL') {
+              handleSaveMidiNotes(st.id, st.trackId, st.target_id, st.notes || []);
+              showToast('Đã lưu Piano Roll', 'success');
+            } else if (st.type === 'SECTION') {
+              handleSaveSectionTab(st.id);
+              showToast('Đã lưu Section Tab', 'success');
+            } else if (st.buffer) {
+              const subTrack = activeTracksRef.current.find(t => t.id === st.trackId);
+              if (subTrack) {
+                updateActiveTracks(prev => prev.map(t => t.id === st.trackId ? { ...t, buffer: st.buffer } : t));
+              }
+              showToast('Đã lưu Audio Tab', 'success');
+            }
+          }
+        }
         return;
       }
       if (!ctrl && !alt && e.key === 's') {
diff --git a/app/static/js/app.precompiled.js b/app/static/js/app.precompiled.js
index 8159fbc..8d0a4da 100644
--- a/app/static/js/app.precompiled.js
+++ b/app/static/js/app.precompiled.js
@@ -207,7 +207,10 @@ const handleUndoRef=useRef(handleUndo);const handleRedoRef=useRef(handleRedo);ha
 const segmentData=data.subarray(startSample,endSample);const addedSamples=len*(loopCount-1);const newBuffer=ctx.createBuffer(1,data.length+addedSamples,sr);const newData=newBuffer.getChannelData(0);let idx=0;for(let i=0;i<endSample;i++)newData[idx++]=data[i];for(let n=0;n<loopCount-1;n++){for(let i=0;i<len;i++)newData[idx++]=segmentData[i];}for(let i=endSample;i<data.length;i++)newData[idx++]=data[i];setSubTabs(prev=>prev.map(s=>s.id===tabId?{...s,buffer:newBuffer,selectionStart:null,selectionEnd:null}:s));showToast(`Đã lặp vùng chọn ${loopCount} lần.`,'success');};useEffect(()=>{const handler=e=>{// Bypass global hotkeys when typing inside input/textarea/contentEditable elements
 if(e.target&&(e.target.tagName==='INPUT'||e.target.tagName==='TEXTAREA'||e.target.isContentEditable)){return;}const ctrl=e.ctrlKey||e.metaKey;const alt=e.altKey;// Global space play/pause shortcut for transport
 if(e.key===' '||e.code==='Space'){e.preventDefault();if(recordingState==='RECORDING'||recordingState==='COUNT_IN'){handleRecordClick();return;}if(handlePlayPauseRef.current)handlePlayPauseRef.current();return;}if(activeTabRef.current!=='main'){// Sub-Tab keyboard shortcuts mapping
-const curTabId=activeTabRef.current;if(ctrl&&alt&&e.key==='n'){e.preventDefault();handleSubTabNormalize(curTabId);return;}if(e.key==='f'||e.key==='F'){e.preventDefault();handleSubTabFade(curTabId,'in');return;}if(e.key==='g'||e.key==='G'){e.preventDefault();handleSubTabFade(curTabId,'out');return;}if(ctrl&&e.key==='l'){e.preventDefault();handleSubTabLoop(curTabId,4);return;}if(e.key==='v'||e.key==='V'){e.preventDefault();const val=prompt("Nhập Gain điều chỉnh (dB):","0");if(val)handleSubTabGain(curTabId,parseFloat(val)||0);return;}if(ctrl&&e.key==='x'){e.preventDefault();handleSubTabCut(curTabId);return;}if(ctrl&&e.key==='c'){e.preventDefault();handleSubTabCopy(curTabId);return;}if(ctrl&&e.key==='v'){e.preventDefault();handleSubTabPaste(curTabId);return;}if(e.key==='Delete'||e.key==='Backspace'||e.key==='Del'){e.preventDefault();if(subTabSelectedNodeTimeRef.current!==null){const selTime=subTabSelectedNodeTimeRef.current;setSubTabs(prev=>prev.map(s=>{if(s.id!==curTabId)return s;const curNodes=s.graphMode==='pan'?s.panningNodes||[]:s.volumeNodes||[];const updated=curNodes.filter(n=>n.time!==selTime);return{...s,[s.graphMode==='pan'?'panningNodes':'volumeNodes']:updated};}));setSubTabSelectedNodeTime(null);}else{handleSubTabDelete(curTabId);}return;}return;}if(ctrl&&e.key==='z'&&!e.shiftKey){e.preventDefault();handleUndoRef.current();return;}if(ctrl&&(e.key==='y'||e.key==='z'&&e.shiftKey)){e.preventDefault();handleRedoRef.current();return;}if(ctrl&&!alt&&e.key==='o'){e.preventDefault();handleImportSFS();return;}if(ctrl&&!alt&&e.key==='n'){e.preventDefault();setTracks([{id:'1',name:'Track 01',buffer:null,startTime:0,volumeDb:0,pan:0,muted:false,solo:false,color:'#0f766e',markers:[],serverFileId:null},{id:'2',name:'Track 02',buffer:null,startTime:0,volumeDb:0,pan:0,muted:false,solo:false,color:'#1d4ed8',markers:[],serverFileId:null}]);setSelectedTrackId('1');showToast('New project created','info');return;}if(ctrl&&!alt&&e.key==='s'){e.preventDefault();handleExportSFS();return;}if(ctrl&&alt&&e.key==='s'||ctrl&&e.shiftKey&&e.key==='s'){e.preventDefault();handleExportSFS();return;}if(ctrl&&!alt&&e.key==='i'){e.preventDefault();addNewTrack();return;}if(ctrl&&alt&&e.key==='i'){e.preventDefault();showToast('Import audio','info');return;}if(ctrl&&!alt&&e.key==='e'){e.preventDefault();openTempTab();return;}if(ctrl&&!alt&&e.key==='m'){e.preventDefault();handleMergeTracks();return;}if(ctrl&&!alt&&e.key==='c'){e.preventDefault();handleCopyTrack();return;}if(ctrl&&!alt&&e.key==='x'){e.preventDefault();handleCutTrack();return;}if(ctrl&&!alt&&e.key==='v'){e.preventDefault();handlePasteTrack();return;}if(e.key==='Delete'||e.key==='Backspace'||e.key==='Del'){const selClip=selectedClipIdRef.current;if(selClip){e.preventDefault();const{trackId,clipId}=selClip;setTracks(prev=>{const track=prev.find(t=>t.id===trackId);if(!track)return prev;const beforeSnap=captureTrackSnapshotRef.current?captureTrackSnapshotRef.current(trackId):null;const updatedClips=(track.clips||[]).filter(c=>c.id!==clipId);const updatedTracks=prev.map(t=>{if(t.id===trackId){return{...t,clips:updatedClips,buffer:updatedClips.length>0?updatedClips[0].buffer:null,startTime:updatedClips.length>0?updatedClips[0].startTime:0,name:updatedClips.length>0?updatedClips[0].name:`Track ${t.id}`};}return t;});setTimeout(()=>{const afterSnap=captureTrackSnapshotRef.current?captureTrackSnapshotRef.current(trackId):null;pushAction('DELETE_CLIP',trackId,beforeSnap,afterSnap);},50);return updatedTracks;});setSelectedClipId(null);showToast('Đã xóa clip.','info');return;}else{e.preventDefault();handleDeleteTrack();return;}}if(ctrl&&!alt&&e.key==='s'){e.preventDefault();handleSaveProject();return;}if(!ctrl&&!alt&&e.key==='s'){e.preventDefault();handleSplitTrack(selectedTrackId);return;}};window.addEventListener('keydown',handler);return()=>window.removeEventListener('keydown',handler);},[]);// ── Temp Tab: draw isolated waveform ──
+const curTabId=activeTabRef.current;if(ctrl&&alt&&e.key==='n'){e.preventDefault();handleSubTabNormalize(curTabId);return;}if(e.key==='f'||e.key==='F'){e.preventDefault();handleSubTabFade(curTabId,'in');return;}if(e.key==='g'||e.key==='G'){e.preventDefault();handleSubTabFade(curTabId,'out');return;}if(ctrl&&e.key==='l'){e.preventDefault();handleSubTabLoop(curTabId,4);return;}if(e.key==='v'||e.key==='V'){e.preventDefault();const val=prompt("Nhập Gain điều chỉnh (dB):","0");if(val)handleSubTabGain(curTabId,parseFloat(val)||0);return;}if(ctrl&&e.key==='x'){e.preventDefault();handleSubTabCut(curTabId);return;}if(ctrl&&e.key==='c'){e.preventDefault();handleSubTabCopy(curTabId);return;}if(ctrl&&e.key==='v'){e.preventDefault();handleSubTabPaste(curTabId);return;}if(e.key==='Delete'||e.key==='Backspace'||e.key==='Del'){e.preventDefault();if(subTabSelectedNodeTimeRef.current!==null){const selTime=subTabSelectedNodeTimeRef.current;setSubTabs(prev=>prev.map(s=>{if(s.id!==curTabId)return s;const curNodes=s.graphMode==='pan'?s.panningNodes||[]:s.volumeNodes||[];const updated=curNodes.filter(n=>n.time!==selTime);return{...s,[s.graphMode==='pan'?'panningNodes':'volumeNodes']:updated};}));setSubTabSelectedNodeTime(null);}else{handleSubTabDelete(curTabId);}return;}return;}if(ctrl&&e.key==='z'&&!e.shiftKey){e.preventDefault();handleUndoRef.current();return;}if(ctrl&&(e.key==='y'||e.key==='z'&&e.shiftKey)){e.preventDefault();handleRedoRef.current();return;}if(ctrl&&!alt&&e.key==='o'){e.preventDefault();handleImportSFS();return;}if(ctrl&&!alt&&e.key==='n'){e.preventDefault();setTracks([{id:'1',name:'Track 01',buffer:null,startTime:0,volumeDb:0,pan:0,muted:false,solo:false,color:'#0f766e',markers:[],serverFileId:null},{id:'2',name:'Track 02',buffer:null,startTime:0,volumeDb:0,pan:0,muted:false,solo:false,color:'#1d4ed8',markers:[],serverFileId:null}]);setSelectedTrackId('1');showToast('New project created','info');return;}if(ctrl&&!alt&&e.key==='s'){e.preventDefault();handleExportSFS();return;}if(ctrl&&alt&&e.key==='s'||ctrl&&e.shiftKey&&e.key==='s'){e.preventDefault();handleExportSFS();return;}if(ctrl&&!alt&&e.key==='i'){e.preventDefault();addNewTrack();return;}if(ctrl&&alt&&e.key==='i'){e.preventDefault();showToast('Import audio','info');return;}if(ctrl&&!alt&&e.key==='e'){e.preventDefault();openTempTab();return;}if(ctrl&&!alt&&e.key==='m'){e.preventDefault();handleMergeTracks();return;}if(ctrl&&!alt&&e.key==='c'){e.preventDefault();handleCopyTrack();return;}if(ctrl&&!alt&&e.key==='x'){e.preventDefault();handleCutTrack();return;}if(ctrl&&!alt&&e.key==='v'){e.preventDefault();handlePasteTrack();return;}if(e.key==='Delete'||e.key==='Backspace'||e.key==='Del'){const selClip=selectedClipIdRef.current;if(selClip){e.preventDefault();const{trackId,clipId}=selClip;setTracks(prev=>{const track=prev.find(t=>t.id===trackId);if(!track)return prev;const beforeSnap=captureTrackSnapshotRef.current?captureTrackSnapshotRef.current(trackId):null;const updatedClips=(track.clips||[]).filter(c=>c.id!==clipId);const updatedTracks=prev.map(t=>{if(t.id===trackId){return{...t,clips:updatedClips,buffer:updatedClips.length>0?updatedClips[0].buffer:null,startTime:updatedClips.length>0?updatedClips[0].startTime:0,name:updatedClips.length>0?updatedClips[0].name:`Track ${t.id}`};}return t;});setTimeout(()=>{const afterSnap=captureTrackSnapshotRef.current?captureTrackSnapshotRef.current(trackId):null;pushAction('DELETE_CLIP',trackId,beforeSnap,afterSnap);},50);return updatedTracks;});setSelectedClipId(null);showToast('Đã xóa clip.','info');return;}else{e.preventDefault();handleDeleteTrack();return;}}if(ctrl&&!alt&&e.key==='s'){e.preventDefault();const curTab=activeTabRef.current;if(curTab==='main'){// Main session: save project + save all dirty sub-tabs
+handleSaveProject();subTabsRef.current.filter(s=>s.isDirty).forEach(st=>{if(st.type==='PIANO_ROLL'){handleSaveMidiNotes(st.id,st.trackId,st.target_id,st.notes||[]);}else if(st.type==='SECTION'){handleSaveSectionTab(st.id);}else if(st.buffer){// Audio clip sub-tab: save buffer to track
+const subTrack=activeTracksRef.current.find(t=>t.id===st.trackId);if(subTrack){updateActiveTracks(prev=>prev.map(t=>t.id===st.trackId?{...t,buffer:st.buffer}:t));}}showToast('Đã lưu','success');});}else{// Sub-tab: save current tab
+const st=subTabsRef.current.find(s=>s.id===curTab);if(st){if(st.type==='PIANO_ROLL'){handleSaveMidiNotes(st.id,st.trackId,st.target_id,st.notes||[]);showToast('Đã lưu Piano Roll','success');}else if(st.type==='SECTION'){handleSaveSectionTab(st.id);showToast('Đã lưu Section Tab','success');}else if(st.buffer){const subTrack=activeTracksRef.current.find(t=>t.id===st.trackId);if(subTrack){updateActiveTracks(prev=>prev.map(t=>t.id===st.trackId?{...t,buffer:st.buffer}:t));}showToast('Đã lưu Audio Tab','success');}}}return;}if(!ctrl&&!alt&&e.key==='s'){e.preventDefault();handleSplitTrack(selectedTrackId);return;}};window.addEventListener('keydown',handler);return()=>window.removeEventListener('keydown',handler);},[]);// ── Temp Tab: draw isolated waveform ──
 useEffect(()=>{if(!tempTabActive||!tempTabBuffer||!tempTabCanvasRef.current)return;const canvas=tempTabCanvasRef.current;const ctx=canvas.getContext('2d');const dpr=window.devicePixelRatio||1;const rect=canvas.getBoundingClientRect();canvas.width=rect.width*dpr;canvas.height=rect.height*dpr;ctx.scale(dpr,dpr);const w=rect.width;const h=rect.height;ctx.fillStyle='#181818';ctx.fillRect(0,0,w,h);const data=tempTabBuffer.getChannelData(0);const sr=tempTabBuffer.sampleRate;const totalSamples=data.length;if(totalSamples===0)return;ctx.strokeStyle='#6ee7b7';ctx.lineWidth=1;for(let px=0;px<w;px++){const startSample=Math.floor(px/w*totalSamples);const endSample=Math.floor((px+1)/w*totalSamples);let maxVal=0;for(let i=startSample;i<endSample&&i<totalSamples;i++){const abs=Math.abs(data[i]);if(abs>maxVal)maxVal=abs;}const mid=h/2;const peakHeight=maxVal*(h*0.4);ctx.beginPath();ctx.moveTo(px,mid-peakHeight);ctx.lineTo(px,mid+peakHeight);ctx.stroke();}},[tempTabActive,tempTabBuffer]);// ── Sub Tab: open as new tab instead of modal (LOOP_EDITOR_2.md §1) ──
 const openTempTab=()=>{const useLocal=selectionMode==='local'&&localSelectionTrackId;const trackId=useLocal?localSelectionTrackId:selectedTrackId;const t=tracks.find(x=>x.id===trackId);if(!t||!t.buffer){showToast('Vui lòng chọn track có dữ liệu âm thanh.','warning');return;}if(selLeft===null||selRight===null||selRight<=selLeft){showToast('Vui lòng chọn một khoảng thời gian trên sóng âm.','warning');return;}// Check if a subtab for this track+range already exists
 const existing=subTabs.find(s=>s.trackId===trackId&&s.startTime===selLeft&&s.endTime===selRight);if(existing){setActiveTab(existing.id);showToast(`Sub Tab already open.`,'info');return;}const sr=t.buffer.sampleRate;const trackStart=t.startTime||0;const relSelLeft=Math.max(0,selLeft-trackStart);const relSelRight=Math.max(0,selRight-trackStart);const startSample=Math.max(0,Math.floor(relSelLeft*sr));const endSample=Math.min(t.buffer.length,Math.floor(relSelRight*sr));const len=endSample-startSample;if(len<100){showToast('Khoảng chọn quá ngắn.','warning');return;}const ctx=getAudioContext();const numChannels=t.buffer.numberOfChannels||1;const subBuffer=ctx.createBuffer(numChannels,len,sr);for(let c=0;c<numChannels;c++){subBuffer.copyToChannel(t.buffer.getChannelData(c).subarray(startSample,endSample),c);}const subChannelInfo=window.SonicAudio.analyzeAudioBufferChannels(subBuffer);const tabId='subtab_'+Date.now();const tabLabel=`Edit_${t.name.replace('.wav','').slice(0,10)}_${selLeft.toFixed(1)}s`;setSubTabs(prev=>[...prev,{id:tabId,label:tabLabel,trackId:trackId,startTime:selLeft,endTime:selRight,buffer:subBuffer,channelInfo:subChannelInfo,effects:{reverse:false,gainDb:0,fadeInMs:0,fadeOutMs:0,normalizeDb:0,pitch:0,speedStretch:100},currentTime:0,selectionStart:null,selectionEnd:null,isPlaying:false,speed:1.0,volumeNodes:[],panningNodes:[],fadeInLen:0,fadeOutLen:0,graphMode:null,isLooping:false,loopCount:0}]);setActiveTab(tabId);};const handleEditClipInSubTab=(trackId,clipId)=>{const track=activeTracks.find(t=>t.id===trackId);if(!track)return;const clips=track.clips&&track.clips.length>0?track.clips:track.buffer?[{id:'default_'+track.id,buffer:track.buffer,startTime:track.startTime||0,name:track.name}]:[];const clip=clips.find(c=>c.id===clipId||clipId==='default'&&c.id==='default_'+trackId);if(!clip||!clip.buffer)return;const resolvedClipId=clip.id==='default'?'default_'+trackId:clip.id;const existing=subTabs.find(s=>s.clipId===resolvedClipId&&s.trackId===trackId);if(existing){setActiveTab(existing.id);showToast(`Sub Tab for "${clip.name}" already open.`,'info');return;}const sr=clip.buffer.sampleRate;const len=clip.buffer.length;const numChannels=clip.buffer.numberOfChannels||1;const ctx=getAudioContext();const subBuffer=ctx.createBuffer(numChannels,len,sr);for(let c=0;c<numChannels;c++){subBuffer.copyToChannel(clip.buffer.getChannelData(c),c);}const subChannelInfo=window.SonicAudio.analyzeAudioBufferChannels(subBuffer);const tabId='subtab_'+Date.now();const tabLabel=`Edit_${clip.name.replace('.wav','').slice(0,10)}`;setSubTabs(prev=>[...prev,{id:tabId,label:tabLabel,trackId:trackId,clipId:resolvedClipId,startTime:clip.startTime,endTime:clip.startTime+clip.buffer.duration,buffer:subBuffer,channelInfo:subChannelInfo,effects:{reverse:false,gainDb:0,fadeInMs:0,fadeOutMs:0,normalizeDb:0,pitch:0,speedStretch:100},currentTime:0,selectionStart:null,selectionEnd:null,isPlaying:false,speed:1.0,volumeNodes:[],panningNodes:[],fadeInLen:0,fadeOutLen:0,graphMode:null,isLooping:false,loopCount:0}]);setActiveTab(tabId);};const handleEditMidiInTab=(trackId,midiItemId)=>{const track=activeTracks.find(t=>t.id===trackId);if(!track)return;const midiItem=(track.midiItems||[]).find(m=>m.id===midiItemId);if(!midiItem)return;const existing=subTabs.find(s=>s.type==='PIANO_ROLL'&&s.target_id===midiItemId);if(existing){setActiveTab(existing.id);showToast('Piano Roll cho nốt MIDI đã được mở.','info');return;}const tabId='midi_'+Date.now();const tabLabel=`Piano Roll: ${midiItem.name||'MIDI'}`;const ctx=getAudioContext();const silentBuffer=ctx.createBuffer(1,128,ctx.sampleRate);const newTab={id:tabId,label:tabLabel,type:'PIANO_ROLL',trackId:trackId,target_id:midiItemId,parent_tab_id:activeTab==='main'?null:activeTab,notes:midiItem.notes||[],duration:midiItem.duration||4,buffer:silentBuffer,instrumentProgram:track.instrumentProgram,instrumentName:track.instrumentName,currentTime:0,isPlaying:false,selectionStart:null,selectionEnd:null,viewport_start_bar:0.0,viewport_bar_width:8.0,scroll_y_pitch:60,snap_resolution:snapValue||"1/16",note_selection:[]};setSubTabs(prev=>[...prev,newTab]);setActiveTab(tabId);};const handleUpdateMidiNotes=(tabId,notes)=>{setSubTabs(prev=>prev.map(s=>s.id===tabId?{...s,notes:notes,isDirty:true}:s));};const handleSaveMidiNotes=(tabId,trackId,midiItemId,updatedNotes)=>{const pianoRollTab=subTabs.find(s=>s.id===tabId);const parentTabId=pianoRollTab?pianoRollTab.parent_tab_id:null;if(parentTabId&&parentTabId.startsWith('session_')){setSessionTabs(prev=>prev.map(s=>{if(s.id!==parentTabId)return s;return{...s,tracks:s.tracks.map(t=>{if(t.id!==trackId)return t;return{...t,midiItems:(t.midiItems||[]).map(m=>{if(m.id!==midiItemId)return m;return{...m,notes:updatedNotes};})};})};}));}else{setTracks(prev=>prev.map(t=>{if(t.id!==trackId)return t;return{...t,midiItems:(t.midiItems||[]).map(m=>{if(m.id!==midiItemId)return m;return{...m,notes:updatedNotes};})};}));}setSubTabs(prev=>prev.map(s=>s.id===tabId?{...s,isDirty:false}:s));showToast('Đã lưu các chỉnh sửa nốt MIDI vào item cha!','success');};const handleSaveSectionTab=tabId=>{const tab=sessionTabs.find(s=>s.id===tabId);if(!tab)return;const bpmVal=parseInt(bpm)||120;const secondsPerBeat=60.0/bpmVal;const secondsPerBar=secondsPerBeat*4;const contentTracks=tab.tracks?tab.tracks.filter(tr=>tr.clips?.length>0||tr.midiItems?.length>0):[];let maxEndTime=0;(contentTracks||[]).forEach(tr=>{(tr.clips||[]).forEach(c=>{const end=(c.startTime||0)+(c.buffer?c.buffer.duration/(c.speed||1.0):4);if(end>maxEndTime)maxEndTime=end;});(tr.midiItems||[]).forEach(m=>{const end=(m.startTime||0)+(m.duration||4);if(end>maxEndTime)maxEndTime=end;});});const durationSec=Math.max(maxEndTime,4*secondsPerBar);setTracks(prev=>prev.map(t=>{if(!t.sections||t.sections.length===0)return t;return{...t,sections:t.sections.map(s=>{if(s.sectionId!==tab.sectionId&&s.id!==tab.sectionId)return s;return{...s,name:tab.name,duration:durationSec,tracks:contentTracks};})};}));// Clear isDirty flag