diff --git a/src/gui/gui.h b/src/gui/gui.h
index 7cc66c84..b3bf1af1 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -1016,7 +1016,7 @@ class FurnaceGUI {
   void drawSSGEnv(unsigned char type, const ImVec2& size);
   void drawWaveform(unsigned char type, bool opz, const ImVec2& size);
   void drawAlgorithm(unsigned char alg, FurnaceGUIFMAlgs algType, const ImVec2& size);
-  void drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, float maxTl, float maxArDr, const ImVec2& size);
+  void drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, unsigned char sus, float maxTl, float maxArDr, const ImVec2& size);
   void drawSysConf(int i);
 
   // these ones offer ctrl-wheel fine value changes.
diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 3e141612..05df40ad 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -901,7 +901,7 @@ void FurnaceGUI::drawAlgorithm(unsigned char alg, FurnaceGUIFMAlgs algType, cons
   }
 }
 
-void FurnaceGUI::drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, float maxTl, float maxArDr, const ImVec2& size) {
+void FurnaceGUI::drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, unsigned char sus, float maxTl, float maxArDr, const ImVec2& size) {
   ImDrawList* dl=ImGui::GetWindowDrawList();
   ImGuiWindow* window=ImGui::GetCurrentWindow();
 
@@ -1806,7 +1806,7 @@ void FurnaceGUI::drawInsEdit() {
                     }
 
                     ImGui::TableNextColumn();
-                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,sliderHeight));
+                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,ins->fm.op->sus,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,sliderHeight));
 
                     ImGui::PopID();
                   }
@@ -1889,7 +1889,7 @@ void FurnaceGUI::drawInsEdit() {
                     }
 
                     //52.0 controls vert scaling; default 96
-                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,52.0*dpiScale));
+                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,ins->fm.op->sus,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,52.0*dpiScale));
                     //P(CWSliderScalar(FM_NAME(FM_AR),ImGuiDataType_U8,&op.ar,&_ZERO,&_THIRTY_ONE)); rightClickable
                     if (ImGui::BeginTable("opParams",2,ImGuiTableFlags_SizingStretchProp)) {
                       ImGui::TableSetupColumn("c0",ImGuiTableColumnFlags_WidthStretch,0.0); \