Fix 'nominal in frequency' setting reading in Pref_Gui

In the old Registry preferences storage system, the 'frequency in nominal' value was stored as an index of the `Cbx_Freq_Input` combobox control in the `Pref_Gui` preferences form. However, the new Settings system stores the frequency value literally. To work around this, we set the combobox selectedindex value to the first full match with the loaded Settings value. When saving, the value of the selecteditem is read directly into the Settings value.

Author: gbakeman

WinNUT_V2/WinNUT-Client/Pref_Gui.vb

@@ -36,7 +36,7 @@ Public Class Pref_Gui
             My.Settings.NUT_AutoReconnect = Cb_Reconnect.Checked
             My.Settings.CAL_VoltInMin = CInt(Tb_InV_Min.Text)
             My.Settings.CAL_VoltInMax = CInt(Tb_InV_Max.Text)
-            My.Settings.CAL_FreqInNom = Cbx_Freq_Input.SelectedIndex
+            My.Settings.CAL_FreqInNom = Cbx_Freq_Input.SelectedItem
             My.Settings.CAL_FreqInMin = CInt(Tb_InF_Min.Text)
             My.Settings.CAL_FreqInMax = CInt(Tb_InF_Max.Text)
             My.Settings.CAL_VoltOutMin = CInt(Tb_OutV_Min.Text)
@@ -116,7 +116,7 @@ Public Class Pref_Gui
             Cb_Reconnect.Checked = My.Settings.NUT_AutoReconnect
             Tb_InV_Min.Text = My.Settings.CAL_VoltInMin
             Tb_InV_Max.Text = My.Settings.CAL_VoltInMax
-            Cbx_Freq_Input.SelectedIndex = My.Settings.CAL_FreqInNom
+            Cbx_Freq_Input.SelectedIndex = Cbx_Freq_Input.FindStringExact(My.Settings.CAL_FreqInNom)
             Tb_InF_Min.Text = My.Settings.CAL_FreqInMin
             Tb_InF_Max.Text = My.Settings.CAL_FreqInMax
             Tb_OutV_Min.Text = My.Settings.CAL_VoltOutMin
@@ -188,7 +188,7 @@ Public Class Pref_Gui
         Catch Except As Exception
             IsShowed = False
             Close()
-            LogFile.LogTracing("Error on Opening Pref_Gui.", LogLvl.LOG_ERROR, Me)
+            LogFile.LogTracing("Error on Opening Pref_Gui:" & vbNewLine & Except.ToString(), LogLvl.LOG_ERROR, Me)
         End Try
     End Sub