diff --git a/src/gui/fmPreview.cpp b/src/gui/fmPreview.cpp
index 9e9ba6a10..ea1249107 100644
--- a/src/gui/fmPreview.cpp
+++ b/src/gui/fmPreview.cpp
@@ -33,7 +33,7 @@
   OPN2_Write((ym3438_t*)fmPreviewOPN,1,(val)); \
   do { \
     OPN2_Clock((ym3438_t*)fmPreviewOPN,out); \
-  } while (((ym3438_t*)fmPreviewOPN)->write_busy); \
+  } while (((ym3438_t*)fmPreviewOPN)->write_busy);
 
 const unsigned char dtTableFMP[8]={
   7,6,5,0,1,2,3,4
@@ -48,7 +48,7 @@ void FurnaceGUI::renderFMPreviewOPN(const DivInstrumentFM& params, int pos) {
   bool mult0=false;
 
   if (pos==0) {
-    OPN2_Reset((ym3438_t*)fmPreviewOPN); 
+    OPN2_Reset((ym3438_t*)fmPreviewOPN);
     OPN2_SetChipType((ym3438_t*)fmPreviewOPN,ym3438_mode_opn);
 
     // set params
@@ -89,7 +89,62 @@ void FurnaceGUI::renderFMPreviewOPN(const DivInstrumentFM& params, int pos) {
   }
 }
 
+#define OPM_WRITE(addr,val) \
+  OPM_Write((opm_t*)fmPreviewOPM,0,(addr)); \
+  do { \
+    OPM_Clock((opm_t*)fmPreviewOPM,out,NULL,NULL,NULL); \
+  } while (((opm_t*)fmPreviewOPM)->write_busy); \
+  OPM_Write((opm_t*)fmPreviewOPM,1,(val)); \
+  do { \
+    OPM_Clock((opm_t*)fmPreviewOPM,out,NULL,NULL,NULL); \
+  } while (((opm_t*)fmPreviewOPM)->write_busy);
+
 void FurnaceGUI::renderFMPreviewOPM(const DivInstrumentFM& params, int pos) {
+  if (fmPreviewOPM==NULL) {
+    fmPreviewOPM=new opm_t;
+  }
+  int out[2];
+  int aOut=0;
+  bool mult0=false;
+
+  if (pos==0) {
+    OPM_Reset((opm_t*)fmPreviewOPM);
+
+    // set params
+    for (int i=0; i<4; i++) {
+      if ((params.op[i].mult&15)==0) {
+        mult0=true;
+        break;
+      }
+    }
+    for (int i=0; i<4; i++) {
+      const DivInstrumentFM::Operator& op=params.op[i];
+      unsigned short baseAddr=i*8;
+      OPM_WRITE(baseAddr+0x40,(op.mult&15)|(dtTableFMP[op.dt&7]<<4));
+      OPM_WRITE(baseAddr+0x60,op.tl);
+      OPM_WRITE(baseAddr+0x80,(op.ar&31)|(op.rs<<6));
+      OPM_WRITE(baseAddr+0xa0,(op.dr&31)|(op.am<<7));
+      OPM_WRITE(baseAddr+0xc0,(op.d2r&31)|(op.dt2<<6));
+      OPM_WRITE(baseAddr+0xe0,(op.rr&15)|(op.sl<<4));
+    }
+    OPM_WRITE(0x20,(params.alg&7)|((params.fb&7)<<3)|0xc0);
+    OPM_WRITE(0x38,((params.fms&7)<<4)|(params.ams&3));
+    OPM_WRITE(0x28,mult0?0x00:0x10); // frequency
+    OPM_WRITE(0x30,0);
+    OPM_WRITE(0x08,0x78); // key on
+  }
+
+  // render
+  for (int i=0; i<FM_PREVIEW_SIZE; i++) {
+    aOut=0;
+    for (int j=0; j<24; j++) {
+      OPM_Clock((opm_t*)fmPreviewOPM,out,NULL,NULL,NULL);
+    }
+    aOut+=((opm_t*)fmPreviewOPM)->ch_out[0];
+    if (aOut<-32768) aOut=-32768;
+    if (aOut>32767) aOut=32767;
+    fmPreview[i]=aOut;
+  }
 }
 
 void FurnaceGUI::renderFMPreviewOPLL(const DivInstrumentFM& params, int pos) {
diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 1878e8da3..173060067 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -19,6 +19,7 @@
 
 #define _USE_MATH_DEFINES
 #include "gui.h"
+#include "../ta-log.h"
 #include "imgui_internal.h"
 #include "../engine/macroInt.h"
 #include "IconsFontAwesome4.h"
@@ -1302,6 +1303,10 @@ void FurnaceGUI::kvsConfig(DivInstrument* ins) {
   if (ImGui::IsItemClicked(ImGuiMouseButton_Right)) {
     fmPreviewOn=!fmPreviewOn;
   }
+  if (ImGui::IsItemHovered() && CHECK_LONG_HOLD) {
+    NOTIFY_LONG_HOLD;
+    fmPreviewOn=!fmPreviewOn;
+  }
   if (!fmPreviewOn) {
     int opCount=4;
     if (ins->type==DIV_INS_OPLL) opCount=2;