diff --git a/src/libslic3r/Config.hpp b/src/libslic3r/Config.hpp
index 7f826109a..e0544b153 100644
--- a/src/libslic3r/Config.hpp
+++ b/src/libslic3r/Config.hpp
@@ -218,7 +218,7 @@ public:
 
     const T& get_at(size_t i) const { return const_cast<ConfigOptionVector<T>*>(this)->get_at(i); }
 
-    // Resize this vector by duplicating the last value.
+    // Resize this vector by duplicating the /*last*/first value.
     // If the current vector is empty, the default value is used instead.
     void resize(size_t n, const ConfigOption *opt_default = nullptr) override
     {
@@ -238,7 +238,7 @@ public:
                 this->values.resize(n, static_cast<const ConfigOptionVector<T>*>(opt_default)->values.front());
             } else {
                 // Resize by duplicating the last value.
-                this->values.resize(n, this->values.back());
+                this->values.resize(n, this->values./*back*/front());
             }
         }
     }
diff --git a/src/slic3r/GUI/GUI.cpp b/src/slic3r/GUI/GUI.cpp
index df5c1d407..0a27af9fa 100644
--- a/src/slic3r/GUI/GUI.cpp
+++ b/src/slic3r/GUI/GUI.cpp
@@ -154,13 +154,15 @@ void change_opt_value(DynamicPrintConfig& config, const t_config_option_key& opt
 			}
 			else if (config.def()->get(opt_key)->gui_flags.compare("serialized") == 0) {
 				std::string str = boost::any_cast<std::string>(value);
-				if (str.back() == ';') str.pop_back();
-				// Split a string to multiple strings by a semi - colon.This is the old way of storing multi - string values.
-				// Currently used for the post_process config value only.
-				std::vector<std::string> values;
-				boost::split(values, str, boost::is_any_of(";"));
-				if (values.size() == 1 && values[0] == "") 
-					values.resize(0);//break;
+                std::vector<std::string> values {};
+                if (!str.empty()) {
+				    if (str.back() == ';') str.pop_back();
+				    // Split a string to multiple strings by a semi - colon.This is the old way of storing multi - string values.
+				    // Currently used for the post_process config value only.
+				    boost::split(values, str, boost::is_any_of(";"));
+				    if (values.size() == 1 && values[0] == "")
+					    values.resize(0);
+                }
 				config.option<ConfigOptionStrings>(opt_key)->values = values;
 			}
 			else{
diff --git a/src/slic3r/GUI/Preset.cpp b/src/slic3r/GUI/Preset.cpp
index fd2b26458..112a579b0 100644
--- a/src/slic3r/GUI/Preset.cpp
+++ b/src/slic3r/GUI/Preset.cpp
@@ -1053,7 +1053,7 @@ std::vector<std::string> PresetCollection::dirty_options(const Preset *edited, c
     std::vector<std::string> changed;
 	if (edited != nullptr && reference != nullptr) {
         changed = deep_compare ?
-				deep_diff(reference->config, edited->config) :
+				deep_diff(edited->config, reference->config) :
 				reference->config.diff(edited->config);
         // The "compatible_printers" option key is handled differently from the others:
         // It is not mandatory. If the key is missing, it means it is compatible with any printer.