Empty string token causing multiselect box visual bug

[Rolthers]

I am using multiselect boxes to select which search results i want to exclude and include, and when the boxes are cleared, i have some javascript running that sets the tokens to empty strings so that the search can still run without waiting for the tokens to be set again.
However when the tokens are set to empty string by the javascript the multiselect box suddenly becoms twice as big without anything in it.

Hopefully this picture shows the problem, the empty x i can somewhat live with, but the box suddenly doubling in size is what i would like to avoid since it seems like a bug.
Here is the javascript i use to set to token to "" (empty string)

Mostly i just wanna avoid the Multiselect Box doubling in size, but alternate solutions to defaulting the tokens to empty values and still allowing the searches to run are also welcome.

[jeffland]

I'd suggest using something other than an empty string, maybe giving it a label saying "None" in the Input and a value that does nothing in the search. A value that does nothing in the search could be a comment makro saying "Empty Input Selection". This would not only solve the issue of your unnecessarily large multiselect, it would also be more transparent to both users of the dashboard and someone looking at the search.