Hi Ludwa6,
When the documentation says that you can indeed invoke a string containing ActionWidgets, I wonder what the syntax is.
Going back to the genesis of evolution in 5.1.20, I found a post by Mohammad that used this with the help of a macro (but if someone can tell us how to do directly, that would be good).
For curiosity, I've added this short macro :
\define undone-actions()
<$action-sendmessage $message="tm-notify" $param="SampleNotification"/>
\end
And on my uncheck filter :
<$list filter="[!has[draft.of]has:field[task]tag[done]sort[created]]">
<$checkbox tag="done" actions=<<undone-actions>> > ~~<$link/>~~</$checkbox>
</$list>
So when I uncheck, I've now the content of SampleNotification tiddler show in the box notification, nice.
(PS : I don't think you can use tm-remove-tag since according to the doc it's with FieldManglerWidget, not ActionWidgets).
This does not answer the question, but with the use of a field rather than a tag, there is no need to delete it ;)
Sylvain