If you replace the following line
<$view field=caption/>
with this
<$set name="title" filter={{{ [<currentTiddler>has[caption]get[caption]] [<currentTiddler>!has[caption]get[title]] }}}>
<$text text=<<title>> />
</$set>
It does the job.
I am not happy with my filter.
{{{ [<currentTiddler>has[caption]get[caption]] [<currentTiddler>!has[caption]get[title]] }}}
I think it can be shortened using then and else. But I could not figure out the syntax.
