diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index c94585ff2..4be4d7ab0 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -1199,6 +1199,10 @@ float GUI_App::toolbar_icon_scale(const bool is_limited/* = false*/) const
 
     if (is_limited && int_val < 50)
         int_val = 50;
+    else if (int_val < 1) {
+        int_val = 10; //buggy code? issue supermerill/superslicer#854
+        assert(false);
+    }
 
     return 0.01f * int_val * icon_sc;
 }