IZPACK-1161 UserInputPanel - dynamic hiding/unhiding of fields depending on conditions affected by settings of radiobutton fields on the same panel broken

There is a problem with dynamically hiding/unhiding user panel fields bound to conditions that are being changed in the same panel.

Example:
```
<field type="radio" variable="dbsystem" summaryKey="key.dbsystem">
  <spec>
    <choice txt="MSSQL" value="mssql" id="text.dbsystem.mssql" />
    <choice txt="Oracle" value="oracle" id="text.dbsystem.oracle" set="true" />
    <choice txt="SAP Hana" value="hdb" id="text.dbsystem.hana" />
  </spec>
</field>
<field type="staticText" align="left" txt="Please select whether you want to use Oracle RAC (real application clusters) architecture." id="text.orarchsettings.description" conditionid="OraDBSelected" />
  <field type="staticText" align="left" txt="Please select whether you want to use MSSQL named instance." id="text.mssqlarchsettings.description" conditionid="mssqlDBSelected" />
  <field type="space" conditionid="mssqlDBSelected|OraDBSelected" />
  <field type="check" variable="oraarch" conditionid="OraDBSelected" summaryKey="key.dbsystem.oraclerac">
  <spec txt="Use Oracle RAC (real application clusters) architecture." true="true" false="false" set="false" id="text.oraarch.label" />
</field>
```

Displaying of "oraarch" is bound to condition OraDBSelected which is evaluated as true when the "Oracle" radiobutton is selected. "Oracle" is pre-selected by default but the condition is not resolved as true (and therefore the oraarch is not even displayed and the variable resolved).

This means that the panel content has to be refreshed dynamically even on activating to show the current state.