Looks like there has been a change in styling (CSS) with the Splunk update. This should do the trick (note the styling for MasterRow): <row id="MasterRow">
<panel depends="$alwaysHideCSS$">
<title>Single value</title>
<html>
<style>
#MasterRow{display: block;}
#Panel1{width:15% !important;}
#Panel2{width:85% !important;}
</style>
</html>
</panel>
<panel id="Panel1">....</panel>
<panel id="Panel2">....</panel>
</row>
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