diff --git a/modes/AudioApps/MEMLCeliumAudioApp.hpp b/modes/AudioApps/MEMLCeliumAudioApp.hpp
index ba164c1..ad0392a 100644
--- a/modes/AudioApps/MEMLCeliumAudioApp.hpp
+++ b/modes/AudioApps/MEMLCeliumAudioApp.hpp
@@ -32,6 +32,26 @@ public:
     static constexpr float frequencies[nFREQs] = {100, 200, 400,800, 400, 800, 100,1600,100,400,100,50,1600,200,100,800,400};
     static constexpr size_t nVoiceSpaces=7;
 
+    // Focus group bitmasks
+    static constexpr uint32_t kFocusSeq = (1u << 0);
+    static constexpr uint32_t kFocusSyn = (1u << 1);
+
+    // Per-param group membership: params 0-13 = sequencer, 14-63 = synthesis
+    static constexpr std::array<uint32_t, NPARAMS> kParamGroupMask = {
+        // 0-13: sequencer (14 entries)
+        kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq,
+        kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq, kFocusSeq,
+        // 14-63: synthesis (50 entries)
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn, kFocusSyn,
+        kFocusSyn,
+    };
+
     std::array<VoiceSpace<NPARAMS>, nVoiceSpaces> voiceSpaces;
 
     VoiceSpaceFn<NPARAMS> currentVoiceSpace;
diff --git a/modes/MEMLNautModeMEMLCelium.hpp b/modes/MEMLNautModeMEMLCelium.hpp
index af40f5c..6e2d9ab 100644
--- a/modes/MEMLNautModeMEMLCelium.hpp
+++ b/modes/MEMLNautModeMEMLCelium.hpp
@@ -2,9 +2,11 @@
 
 #include "../src/memllib/interface/MIDIInOut.hpp"
 #include "../src/memllib/hardware/memlnaut/display/XYPadView.hpp"
+#include "../src/memllib/hardware/memlnaut/display/BlockSelectView.hpp"
 #include "../src/memllib/hardware/memlnaut/MEMLNaut.hpp"
 #include "AudioApps/MEMLCeliumAudioApp.hpp"
 #include "../src/memllib/examples/InterfaceRL.hpp"
+#include "../src/memllib/audio/FocusManager.hpp"
 #include "../src/memllib/PicoDefs.hpp"
 #include "MEMLNautMode.hpp"
 #include <memory>
@@ -22,6 +24,8 @@ public:
 
     bool sequencerPlaying = false;
 
+    FocusManager<MEMLCeliumAudioApp<>::kN_Params, 2> focusManager;
+
 
     void setupInterface() {
         interface.setup(kN_InputParams, MEMLCeliumAudioApp<>::kN_Params);
@@ -29,6 +33,13 @@ public:
         interface.setModeInfo("memlcelium", "MEMLCelium");
         interfacePtr = make_non_owning(interface);
 
+        focusManager.setGroupName(0, "Seq");
+        focusManager.setGroupName(1, "Synth");
+        focusManager.setParamGroups(MEMLCeliumAudioApp<>::kParamGroupMask);
+        interface.paramTransformHook = [this](std::vector<float>& p) {
+            focusManager.applyInPlace(p);
+        };
+
         MEMLNaut::Instance()->setTogA2Callback([this](bool state) { // scr_ref no longer captured directly
             Serial.println(state ? "TogA2 ON" : "TogA2 OFF");
             if (state) {
@@ -76,6 +87,19 @@ public:
     }
 
     void addViews() {
+        // Focus screen — select which parameter groups are live
+        auto focusView = std::make_shared<BlockSelectView>(
+            "Focus", TFT_CYAN, 2, 120, 70, TFT_BLACK,
+            std::vector<String>{"Seq", "Synth"}, TFT_DARKGREY, 2);
+
+        focusView->SetOnSelectCallback([this, focusView](size_t id) {
+            size_t groupIdx = id - 1;
+            uint32_t newMask = focusManager.getSelectedMask() ^ (1u << groupIdx);
+            focusManager.setFocus(newMask, interface.getLastAction());
+            focusView->toggleAlt(groupIdx);
+        });
+        MEMLNaut::Instance()->disp->InsertViewAfter(interface.rlStatsView, focusView);
+
         std::shared_ptr<VoiceSpaceSelectView> voiceSpaceSelectView;
         voiceSpaceSelectView = std::make_shared<VoiceSpaceSelectView>("Voice Spaces");
 
diff --git a/src/memllib b/src/memllib
index 6bf7d2c..188496d 160000
--- a/src/memllib
+++ b/src/memllib
@@ -1 +1 @@
-Subproject commit 6bf7d2c362541047f02fdbf2f6dc359873bcd51f
+Subproject commit 188496d4621cec7008d83404b80578597b67414b