You can set and unset tokens to show/hide dropdowns. Here is an example.
<form>
<panel>
<title>Set sourcetype token</title>
<input type="dropdown" token="field1">
<label>Select Sourcetype</label>
<choice value="1">eml</choice>
<choice value="2">http_access_log</choice>
<choice value="3">jvm</choice>
<choice value="4">layer7</choice>
<choice value="5">waspmi</choice>
<change>
<!-- For the sourcetype field clicked: -->
<!-- Set token to display a chart -->
<!-- Unset token to display a table -->
<condition value="1">
<set token="sourcetype"></set>
<set token="show1">foo</set>
<unset token="show2"></unset>
<unset token="show3"></unset>
</condition>
<!-- For any other field clicked: -->
<!-- Set token to display a table -->
<!-- Unset token to display a chart -->
<condition value="2">
<set token="sourcetype"></set>
<set token="show2">foo</set>
<unset token="show1"></unset>
<unset token="show3"></unset>
</condition>
<condition value="3">
<set token="sourcetype"></set>
<set token="show3">foo</set>
<unset token="show2">foo</unset>
<unset token="show1"></unset>
</condition>
</change>
</input>
</panel>
<panel>
<input type="dropdown" token="field2" searchWhenChanged="true" depends="$show1$">
<label>Index</label>
<choice value="eml">eeml</choice>
<choice value="http">http</choice>
<choice value="layer7">layer7</choice>
</input>
<input type="dropdown" token="field4" searchWhenChanged="true" depends="$show2$">
<label>JVM Name</label>
<choice value="eml">eeml</choice>
<choice value="http">http</choice>
<choice value="layer7">layer7</choice>
</input>
<input type="dropdown" token="field4" searchWhenChanged="true" depends="$show3$">
<label>Host Name</label>
<choice value="eml">eeml</choice>
<choice value="http">http</choice>
<choice value="layer7">layer7</choice>
</input>
<html rejects="$show1$, $show2$, $show3$">
<h2>Details</h2>
<div style="padding: 50px; margin: 0 auto; width: 350px;">
<div class="alert alert-warning">
<i class="icon-alert"/>
Click on a row in the table on the left to show details.
</div>
</div>
</html>
</panel>
