I am sorry but I did not see your prior post on this issue so I'm a bit late with a response.
I think there is still an issue here.
In the FE the "indexTree" service is invoked from the index tab where there are two options:
1. AdminIndex and 2. AdminIndexAll.
1. AdminIndex does nothing even though the label says "Content ids to index (separate ids with a space)" (fooled you again user)!
The controller only refreshes the view when with target="AdminIndex", form code follows.
<form name="AdminIndex" target="AdminIndex" title="" type="single" header-row-style="header-row" default-table-style="basic-table">
<field name="indexContentIds" position="1"><text size="50"/></field>
<field name="submitButton" title="$
" widget-style="smallSubmit" position="2"><submit button-type="button"/></field>
2. AdminIndexAll runs the "indexTree" service but generates an error when sent the default value WebStoreCONTENT (see screen shot). You no longer get an error when you click the Find button in the Find tab but you do not get any data either.
OOB the Find tab could handle the OOB case of no index more gracefully (present a meaningful message) and I would expect that the default value in the Index tab would result in some records being returned in find.
Also in the Find tab the drop-down list Select Category is empty - what's that about?