[datafeed] make cnxset handling of datafeed source more robust
currently we may run in some cases where the session has no more cnxset
depending on errors and parser's handling of the cnxset.
Also, free the cnxset and reacquire it later, letting a chance to other
threads to run.
<?xml version="1.0" encoding="UTF-8"?>
<display window-flags="sticky, below" width="185" height="200">
<sensor id="r" module="rqlsensor"/>
<sensor id="FS" module="FontSelector,1,Sans 10 black"/>
<!-- left border -->
<group x="0" width="5" height="200" bg-uri="gfx/border-left.png"/>
<image x="10" y="0" uri="gfx/logo_erudi.png"/>
<array id="results" x="10" y="30"
watch="layout=r:layout, length=r:length">
<label id="lbls1" color="black"
on-enter="r:enter-line"
on-leave="r:leave-line"
on-click="r:click-line"
watch="value=r:result, font=FS:font0, color=r:resultbg"/>
</array>
</display>