Fixes to DBC editor (from Viaccess-Orca commit)

dbcmaineditor.cpp

@@ -405,6 +405,7 @@ void DBCMainEditor::refreshNodesTable()
 
     //insert a fresh entry at the bottom that contains nothing
     ui->NodesTable->insertRow(ui->NodesTable->rowCount());
+    ui->NodesTable->selectRow(0);
 }
 
 void DBCMainEditor::refreshMessagesTable(const DBC_NODE *node)

dbcsignaleditor.cpp

@@ -348,6 +348,10 @@ void DBCSignalEditor::addNewSignal()
 void DBCSignalEditor::deleteCurrentSignal()
 {
     int currIdx = ui->signalsList->currentRow();
+
+    if(currIdx==ui->signalsList->count()-1)
+        return;
+
     if (currIdx > -1)
     {
         delete(ui->signalsList->item(currIdx));