Multi-select checklist unless 'All' is selected

Question

I have a search form where the user must tell the form what label(s)/bin(s) they would like to search in. If the user picks nothing, the form defaults them to search 'All Emails', as this will allow them to search on everything OR the user can select one to many labels/bins to search within.

When the user selects 'All Emails', they do not get an option to select other labels/bins, so they are disabled. Unchecking 'All Emails' enables the the other selections.

1. Is this an intuitive control for the user?
2. Is the checkbox vs radio button a viable option here?
3. Should the multi-selected checkboxes clear or disable when 'All' is selected?

The application has 'system labels' such as inbox and sent, that the application creates, and 'custom labels' that the user can create.

Answer 1

Think of the "Select All" option as a button rather than a checkbox, which performs the action of selecting/deselecting all checkboxes (not disabling).

If you click it, it will select all the checkboxes.

Once clicked it transforms into "Deselect All" so clicking it will deselect all checkboxes.

Answer 2

Being a bit old-school, personally I always prefer the classic radio/checkbox combo for this sort of problem:

(o) All Emails
( ) Selected emails
   [ ] Unlabelled
   [ ] Inbox
   [ ] Sent

etc. But admittedly then you still have more decisions to make: whether

• whether to disable or hide the checkboxes when the "All Mails" radio button is selected
• if you do neither, then whether to automatically select the "Selected emails" radio button when the user toggles one of the checkboxes.

Answer 3

Use a partial checkbox

One option is to use the same treatment that Windows has used. They have a separate value for a checkbox in which only some of the child elements are selected:

This allows them to show at a higher level that some but not all of the child elements are selected. In your case, this looks a bit like the relationship you have between "All Emails" and the specific categories (all of the categories together equals "All Emails").

Behavior

The way the Windows implementation behaves is that if you click on the partial checkbox, the box becomes checked and all children of that element are checked as well. Clicking the same parent element's box will uncheck that box and all of its children. In this way, the parent element toggles a check all/uncheck all behavior.

Limitations

This becomes an inconvenient solution when there are a large number of items to check/uncheck, but I guess that's true with any checkbox group.