Custom tooltip problem

[Dave]

I'm having trouble getting the example of custom tooltips at tiddlywiki.com to work

if you go here: https://tiddlywiki.com/#tv-wikilink-tooltip%20Variable%20(Examples)

the underlying code is confusing.  I edited it to this to figure out how its working:

<$importvariables filter="$:/editions/tw5.com/macro-examples/tv-wikilink-tooltip">
"Here is a link to [[backlinks Operator]] with a custom tooltip."
</$importvariables>

I guess everything else is extraneous.  When you hover over the link, the text at the field "custom" of that tiddler shows between round brackets

So what I did in my own TW (same version) was copy the tiddler "$:/editions/tw5.com/macro-examples/tv-wikilink-tooltip" to my TW, then put in a new tiddler (by the same name)

<$importvariables filter="$:/editions/tw5.com/macro-examples/tv-wikilink-tooltip">

[[Some Link|SomeLink]]

</$importvariables>

and in the link tiddler I added the field "caption" and put in some text.  When I hover the mouse over the link however, the tooltip is just an empty set of brackets.

What am I missing?

Thanks,
 - Dave

[Dave]

although I don't know how it works, I figured out that if I just put the info in the field "tooltip" instead of "caption" it works just fine... O_o