diff --git a/bundled_deps/imgui/imgui/imgui_draw.cpp b/bundled_deps/imgui/imgui/imgui_draw.cpp
index 62a470233b..b28e1d39ff 100644
--- a/bundled_deps/imgui/imgui/imgui_draw.cpp
+++ b/bundled_deps/imgui/imgui/imgui_draw.cpp
@@ -3293,7 +3293,7 @@ const ImFontGlyph* ImFont::FindGlyph(ImWchar c) const
     }
     const ImWchar i = IndexLookup.Data[c];
     if (i == (ImWchar)-1) {
-       imgui_rendered_fallback_glyph(c);
+        imgui_rendered_fallback_glyph(c);
         return FallbackGlyph;
     }
     return &Glyphs.Data[i];
diff --git a/src/slic3r/GUI/ImGuiWrapper.cpp b/src/slic3r/GUI/ImGuiWrapper.cpp
index b82c396629..da5b778ed0 100644
--- a/src/slic3r/GUI/ImGuiWrapper.cpp
+++ b/src/slic3r/GUI/ImGuiWrapper.cpp
@@ -57,6 +57,9 @@ bool              s_font_cjk;
 // a fallback glyph for c.
 void imgui_rendered_fallback_glyph(ImWchar c)
 {
+    if (c == 0)
+        return;
+
     if (ImGui::GetIO().Fonts->Fonts[0] == ImGui::GetFont()) {
         // Only do this when we are using the default ImGui font. Otherwise this would conflict with
         // EmbossStyleManager's font handling and we would load glyphs needlessly.