diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index e785fba4..79c567a1 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -708,6 +708,7 @@ const char* ssgEnvTypes[8]={
 
 void FurnaceGUI::drawInsEdit() {
   if (!insEditOpen) return;
+  ImGui::SetNextWindowSizeConstraints(ImVec2(440.0f*dpiScale,400.0f*dpiScale),ImVec2(scrW*dpiScale,scrH*dpiScale));
   if (ImGui::Begin("Instrument Editor",&insEditOpen,ImGuiWindowFlags_NoDocking)) {
     if (curIns<0 || curIns>=(int)e->song.ins.size()) {
       ImGui::Text("no instrument selected");