When molecules are uploaded, show tickboxes by default

[bvreede]

As of #110, when input molecules are uploaded, they show up nicely as index with, for example, the molecule card of the mdref node:

However, to get to this state, you have to click twice on the + button, as the default view for this card does not show any molecules:

This is quite cumbersome; when multiple molecules are loaded they have to each individually be added to this card to even be able to tick the box.

It would be useful, in particular in a situation where molecules are uploaded, when the first, default appearance for this card is named molecules with a tickbox, without having to click repeatedly on the add button.