diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 11e741ec61..b22d3b2409 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -2751,7 +2751,8 @@ void PrintConfigDef::init_fff_params()
     def->label = L("Synchronize with object layers");
     def->category = L("Support material");
     def->tooltip = L("Synchronize support layers with the object print layers. This is useful "
-                   "with multi-material printers, where the extruder switch is expensive.");
+                   "with multi-material printers, where the extruder switch is expensive. "
+                   "This option is only available when top contact Z distance is set to zero.");
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionBool(false));