diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 92f5eb77f..e5f6f9482 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -649,7 +649,8 @@ bool PrintObject::invalidate_state_by_config_options(const std::vector<t_config_
             || opt_key == "support_material_contact_distance_bottom" 
             || opt_key == "xy_size_compensation"
             || opt_key == "hole_size_compensation"
-            || opt_key == "hole_to_polyhole") {
+            || opt_key == "hole_to_polyhole"
+            || opt_key == "z_step") {
             steps.emplace_back(posSlice);
         } else if (opt_key == "support_material") {
             steps.emplace_back(posSupportMaterial);
diff --git a/src/libslic3r/Slicing.cpp b/src/libslic3r/Slicing.cpp
index 06080116c..444fdfc8e 100644
--- a/src/libslic3r/Slicing.cpp
+++ b/src/libslic3r/Slicing.cpp
@@ -23,16 +23,16 @@ namespace Slic3r
 
 static const coordf_t MIN_LAYER_HEIGHT = 0.01;
 static const coordf_t MIN_LAYER_HEIGHT_DEFAULT = 0.07;
-
-inline coordf_t check_z_step(coordf_t val, coordf_t z_step) {
-    uint64_t valint = uint64_t(val * 100000. + 0.1);
-    uint64_t stepint = uint64_t(z_step * 100000. + 0.1);
-    return (((valint + (stepint/2)) / stepint) * stepint) / 100000.;
+// fields are with 8-number precision after the dot
+inline coordf_t check_z_step(const coordf_t val, const coordf_t z_step) {
+    uint64_t valint = uint64_t(val * 100000000. + 0.1);
+    uint64_t stepint = uint64_t(z_step * 100000000. + 0.1);
+    return (((valint + (stepint/2)) / stepint) * stepint) / 100000000.;
     //return int((val + z_step * 0.5) / z_step) * z_step;
 }
-inline bool test_z_step(coordf_t val, coordf_t z_step) {
-    uint64_t valint = uint64_t(val * 100000. + 0.1);
-    uint64_t stepint = uint64_t(z_step * 100000. + 0.1);
+inline bool test_z_step(const coordf_t val, const coordf_t z_step) {
+    uint64_t valint = uint64_t(val * 100000000. + 0.1);
+    uint64_t stepint = uint64_t(z_step * 100000000. + 0.1);
     return valint % stepint == 0;
 }
 
diff --git a/src/libslic3r/Slicing.hpp b/src/libslic3r/Slicing.hpp
index ab76c63c4..1db11a375 100644
--- a/src/libslic3r/Slicing.hpp
+++ b/src/libslic3r/Slicing.hpp
@@ -20,7 +20,7 @@ class PrintConfig;
 class PrintObjectConfig;
 class ModelObject;
 
-coordf_t check_z_step(coordf_t val, coordf_t z_step);
+coordf_t check_z_step(const coordf_t val,const coordf_t z_step);
 
 // Parameters to guide object slicing and support generation.
 // The slicing parameters account for a raft and whether the 1st object layer is printed with a normal or a bridging flow
diff --git a/src/slic3r/GUI/Field.hpp b/src/slic3r/GUI/Field.hpp
index 7a3b4bf8f..5fb1fcd18 100644
--- a/src/slic3r/GUI/Field.hpp
+++ b/src/slic3r/GUI/Field.hpp
@@ -36,7 +36,7 @@ using t_kill_focus = std::function<void(const std::string&)>;
 using t_change = std::function<void(const t_config_option_key&, const boost::any&)>;
 using t_back_to_init = std::function<void(const std::string&)>;
 
-wxString double_to_string(double const value, const int max_precision = 4);
+wxString double_to_string(double const value, const int max_precision = 8);
 
 class RevertButton : public ScalableButton
 {