diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 130c70d5d..f6fff0b3c 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -2824,7 +2824,11 @@ void FurnaceGUI::drawInsEdit() {
         updateFMPreview=false;
       }
       if (settings.insEditColorize) {
-        pushAccentColors(uiColors[GUI_COLOR_INSTR_STD+ins->type],uiColors[GUI_COLOR_INSTR_STD+ins->type],uiColors[GUI_COLOR_INSTR_STD+ins->type],ImVec4(0.0f,0.0f,0.0f,0.0f));
+        if (ins->type>=DIV_INS_MAX) {
+          pushAccentColors(uiColors[GUI_COLOR_INSTR_UNKNOWN],uiColors[GUI_COLOR_INSTR_UNKNOWN],uiColors[GUI_COLOR_INSTR_UNKNOWN],ImVec4(0.0f,0.0f,0.0f,0.0f));
+        } else {
+          pushAccentColors(uiColors[GUI_COLOR_INSTR_STD+ins->type],uiColors[GUI_COLOR_INSTR_STD+ins->type],uiColors[GUI_COLOR_INSTR_STD+ins->type],ImVec4(0.0f,0.0f,0.0f,0.0f));
+        }
       }
       if (ImGui::BeginTable("InsProp",3)) {
         ImGui::TableSetupColumn("c0",ImGuiTableColumnFlags_WidthFixed);