TiddlySpot Saver: Can TiddlyWiki automatically fill in the url according to the current url?

When configuring the TiddlySpot
Saver. is it possible to leave out the url and have tiddlywiki automatically fill in the url according to the current url?

I currently have a multi-site synchronized tiddlywiki. it is not possible to save to the current site.

I want the tiddlywiki opened from whichever URL I click save to be uploaded to the appropriate URL.