Deselecting radio buttons on the participant registration form

As an admin, I want to edit the registration of a participant and to deselect a (usually) mandatory event/item for this participant that is shown as a radio button.
How do I proceed?

If you are a user with administrator or organizer status:

You can deselected such events / items by double clicking on the respective radio button.

For clients who use ConfTool 2.6. and ConfTool Standard:

It is important to know that a group of radio buttons cannot be deselected once selected.
However, you can add an additional event to any event group and call it e.g. "none of the above" so that participants will be able to click on an alternative option if they do not want to choose any of the other options.

Please first edit the event group here:
Overview => Settings => Manage Event/Item Groups
... and for the option "Selection Mode" choose the setting "Exclusive: Use radio buttons so that only one event of this group can be selected". Set the "Minimum number of items to select from this group" to 0 or 1 and the "Maximum Number of Items to Select from This Group" to 1 (see image 1).

Now head on over to the events:
"Overview => Settings => Manage Events and Items"
Create your main events for the event group and add an additional event to it which you can call e.g. "none of the above" / "no choice" (see image 2).

You will find a detailed manual here:
Using event groups to limit choice options for events / items

For clients who use ConfTool 2.8.:

If you also want to allow all participants to be able to deselect a radio button, then you can create a hybrid check box and radio button. Within the group of events, only one item will be selectable. However, unlike within normal radio button groups, participants will be able to deselect any choice by clicking on it again.

Please go to this page:
Overview => Settings => Manage Event/Item Groups
... and open an event group.

For the option "Selection Mode" choose the setting "Exclusive: Use radio buttons so that only one event of this group can be selected".

Move on to the option "Minimum Number of Items to Select from This Group" and set it to "0" (see image 3).
If you set the minimum to 0, items can be deselected by every user by clicking on them again.
If you set the minimum to 1, only admins and organizers can deselect them using a double-click.
Deselectable radio buttons will take on a square shape (see image 4).

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