diff --git a/SavvyCAN.pro b/SavvyCAN.pro
index 7052c48..8d64e4d 100644
--- a/SavvyCAN.pro
+++ b/SavvyCAN.pro
@@ -45,7 +45,8 @@ SOURCES += main.cpp\
     dbc_classes.cpp \
     dbcloadsavewindow.cpp \
     fuzzingwindow.cpp \
-    udsscanwindow.cpp
+    udsscanwindow.cpp \
+    can_structs.cpp
 
 HEADERS  += mainwindow.h \
     can_structs.h \
diff --git a/can_structs.cpp b/can_structs.cpp
new file mode 100644
index 0000000..853c83d
--- /dev/null
+++ b/can_structs.cpp
@@ -0,0 +1,2 @@
+#include "can_structs.h"
+
diff --git a/can_structs.h b/can_structs.h
index 92e4491..e9668bd 100644
--- a/can_structs.h
+++ b/can_structs.h
@@ -1,9 +1,10 @@
 #ifndef CAN_STRUCTS_H
 #define CAN_STRUCTS_H
 
+#include <QVector>
 #include <stdint.h>
 
-struct CANFrame
+class CANFrame
 {
 public:
     int ID;
@@ -26,5 +27,19 @@ public:
     int priority;
     bool isBroadcast;
 };
+
+//the same as the CANFrame struct but with arbitrary data size.
+struct ISOTP_FRAME
+{
+public:
+    int ID;
+    int bus;
+    bool extended;
+    bool isReceived;
+    int len;
+    QVector<unsigned char> data;
+    uint64_t timestamp;
+};
+
 #endif // CAN_STRUCTS_H
 
diff --git a/config.h b/config.h
index 1fe461f..8030d77 100644
--- a/config.h
+++ b/config.h
@@ -1,7 +1,7 @@
 #ifndef CONFIG
 #define CONFIG
 
-#define VERSION             150
+#define VERSION             151
 
 //try to keep this in sync.
 //SavvyCAN will complain if you connect a GVRET board with a revision
diff --git a/graphingwindow.cpp b/graphingwindow.cpp
index 05df3ed..afe9c4d 100644
--- a/graphingwindow.cpp
+++ b/graphingwindow.cpp
@@ -734,6 +734,9 @@ void GraphingWindow::loadDefinitions()
     QStringList filters;
     filters.append(QString(tr("Graph definition (*.gdf)")));
 
+    if (dbcHandler == NULL) return;
+    if (dbcHandler->getFileCount() == 0) dbcHandler->createBlankFile();
+
     dialog.setFileMode(QFileDialog::ExistingFile);
     dialog.setNameFilters(filters);
     dialog.setViewMode(QFileDialog::Detail);