diff --git a/src/input_context.cpp b/src/input_context.cpp
index 17367869fb7d7..b94636efeffff 100644
--- a/src/input_context.cpp
+++ b/src/input_context.cpp
@@ -609,8 +609,8 @@ void keybindings_ui::draw_controls()
     if( last_status != status && status == s_show ) {
         ImGui::SetKeyboardFocusHere( 0 );
     }
-    strncpy( filter_text_impl, filter_text.c_str(), strlen( filter_text.c_str() ) );
-    ImGui::InputText( "##NOLABEL", filter_text_impl, 255,
+    strncpy( filter_text_impl, filter_text.c_str(), filter_text.length() );
+    ImGui::InputText( "##NOLABEL", filter_text_impl, std::extent< decltype( filter_text_impl )>::value,
                       status == s_show ? ImGuiInputTextFlags_None : ImGuiInputTextFlags_ReadOnly );
     filter_text.assign( filter_text_impl );
     ImGui::Separator();