Improve UX for adding multiple tokens

[yorkshire-pudding]

Inserting a token involves selecting one then closing the modal and clicking on the field. If you then want another you have to repeat, staying the tree navigation from the beginning again. You may need to resize and/or move the modal to allow you to click into the field.

I'm not sure what's possible but let's explore what would be best.

Ideas for improvement:

• select multiple and then insert all in field in order after closing modal
• select field first then click each token. There should be some visual feedback that the insertion has happened.
• collapse the modal after selecting a token then restoring once token inserted

[yorkshire-pudding]

Demo of adding multiple tokens with browser staying open.

[yorkshire-pudding]

I think with the changes in #14 , this is completed