diff --git a/src/slic3r/GUI/Preferences.cpp b/src/slic3r/GUI/Preferences.cpp
index 05707b37f2..47574ca70f 100644
--- a/src/slic3r/GUI/Preferences.cpp
+++ b/src/slic3r/GUI/Preferences.cpp
@@ -405,6 +405,8 @@ wxBoxSizer *PreferencesDialog::create_item_input(wxString title, wxString title2
     StateColor input_bg(std::pair<wxColour, int>(wxColour("#F0F0F1"), StateColor::Disabled), std::pair<wxColour, int>(*wxWHITE, StateColor::Enabled));
     input->SetBackgroundColor(input_bg);
     input->GetTextCtrl()->SetValue(app_config->get(param));
+    wxTextValidator validator(wxFILTER_DIGITS);
+    input->GetTextCtrl()->SetValidator(validator);
 
     auto second_title = new wxStaticText(parent, wxID_ANY, title2, wxDefaultPosition, DESIGN_TITLE_SIZE, 0);
     second_title->SetForegroundColour(DESIGN_GRAY900_COLOR);