Howto cancel drop-action based on actionTiddler field?

[Niels Bjerre]

I want to go-ahead or cancel drop-action based on a field-value in the tiddler dropped (actionTiddler)

<$droppable actions=<<droppable-actions>>>......<$droppable>

in droppable-actions i have a <$reveal type="match" state=XXXX value="yyy">

In state=.. i have a problem referring to $(actionTiddler)$!!field

Any tip is much appreciated!

Niels