diff --git a/src/gui/debugWindow.cpp b/src/gui/debugWindow.cpp
index 5dca05edb..2e6412d02 100644
--- a/src/gui/debugWindow.cpp
+++ b/src/gui/debugWindow.cpp
@@ -615,6 +615,7 @@ void FurnaceGUI::drawDebug() {
       ImGui::Text("audio: %dµs",lastProcTime);
       ImGui::Text("render: %.0fµs",(double)renderTimeDelta/perfFreq);
       ImGui::Text("draw: %.0fµs",(double)drawTimeDelta/perfFreq);
+      ImGui::Text("swap: %.0fµs",(double)swapTimeDelta/perfFreq);
       ImGui::Text("layout: %.0fµs",(double)layoutTimeDelta/perfFreq);
       ImGui::Text("event: %.0fµs",(double)eventTimeDelta/perfFreq);
       ImGui::Separator();
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index cebb80b38..d92039d1b 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -6395,14 +6395,17 @@ bool FurnaceGUI::loop() {
       }
     }
     drawTimeEnd=SDL_GetPerformanceCounter();
+    swapTimeBegin=SDL_GetPerformanceCounter();
     rend->present();
     if (settings.renderClearPos) {
       rend->clear(uiColors[GUI_COLOR_BACKGROUND]);
     }
+    swapTimeEnd=SDL_GetPerformanceCounter();
 
     layoutTimeDelta=layoutTimeEnd-layoutTimeBegin;
     renderTimeDelta=renderTimeEnd-renderTimeBegin;
     drawTimeDelta=drawTimeEnd-drawTimeBegin;
+    swapTimeDelta=swapTimeEnd-swapTimeBegin;
     eventTimeDelta=eventTimeEnd-eventTimeBegin;
 
     soloTimeout-=ImGui::GetIO().DeltaTime;
@@ -7595,6 +7598,9 @@ FurnaceGUI::FurnaceGUI():
   drawTimeBegin(0),
   drawTimeEnd(0),
   drawTimeDelta(0),
+  swapTimeBegin(0),
+  swapTimeEnd(0),
+  swapTimeDelta(0),
   eventTimeBegin(0),
   eventTimeEnd(0),
   eventTimeDelta(0),
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 0d0d4f576..00a33cbb9 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -2209,6 +2209,7 @@ class FurnaceGUI {
   uint64_t layoutTimeBegin, layoutTimeEnd, layoutTimeDelta;
   uint64_t renderTimeBegin, renderTimeEnd, renderTimeDelta;
   uint64_t drawTimeBegin, drawTimeEnd, drawTimeDelta;
+  uint64_t swapTimeBegin, swapTimeEnd, swapTimeDelta;
   uint64_t eventTimeBegin, eventTimeEnd, eventTimeDelta;
 
   FurnaceGUIPerfMetric perfMetrics[64];
diff --git a/src/gui/osc.cpp b/src/gui/osc.cpp
index 314b128d1..05cd962f4 100644
--- a/src/gui/osc.cpp
+++ b/src/gui/osc.cpp
@@ -382,6 +382,10 @@ void FurnaceGUI::drawOsc() {
     if (ImGui::IsItemClicked(ImGuiMouseButton_Right)) {
       oscZoomSlider=!oscZoomSlider;
     }
+    if (mobileUI && ImGui::IsItemHovered() && CHECK_LONG_HOLD) {
+      oscZoomSlider=!oscZoomSlider;
+      NOTIFY_LONG_HOLD;
+    }
   }
   if (settings.oscTakesEntireWindow) {
     ImGui::PopStyleVar(3);
diff --git a/src/gui/render/renderGL.cpp b/src/gui/render/renderGL.cpp
index 4e7999d46..19c3daf4a 100644
--- a/src/gui/render/renderGL.cpp
+++ b/src/gui/render/renderGL.cpp
@@ -114,6 +114,8 @@ const char* sh_oscRender_srcF=
   "    if (val>valmax) valmax=val;\n"
   "    if (val<valmin) valmin=val;\n"
   "  }\n"
+  "  if ((fur_fragCoord.y-uLineWidth)>valmax*uResolution.y*0.5) discard;\n"
+  "  if ((fur_fragCoord.y+uLineWidth)<valmin*uResolution.y*0.5) discard;\n"
   "  float slope=abs(valmax-valmin)*uResolution.y*0.5;\n"
   "  float slopeDiv=min(uAdvance,(uAdvance/slope));\n"
   "  float xRight=uv.x+((uLineWidth)/uResolution.x);\n"
@@ -175,6 +177,8 @@ const char* sh_oscRender_srcF=
   "    if (val>valmax) valmax=val;\n"
   "    if (val<valmin) valmin=val;\n"
   "  }\n"
+  "  if ((fur_fragCoord.y-uLineWidth)>valmax*uResolution.y*0.5) discard;\n"
+  "  if ((fur_fragCoord.y+uLineWidth)<valmin*uResolution.y*0.5) discard;\n"
   "  float slope=abs(valmax-valmin)*uResolution.y*0.5;\n"
   "  float slopeDiv=min(uAdvance,(uAdvance/slope));\n"
   "  float xRight=uv.x+((uLineWidth)/uResolution.x);\n"