Implement a "Select All" menu item

[mat-m]

Is your feature request related to a problem? Please describe.

I can't select all items in a folder/mailbox to apply the same action to them, typîcally move or delete.

Describe the solution you'd like

After selecting one element in the messages list, the "Actions on selection" 3-dot menu at the top could benefit from a "Select all" entry, so you can then apply any action on all the emails you have.

Describe alternatives you've considered

There no keybaord shortcut to enable selection like the "S" does for starring.

Additional context

It'a quick win for multiple mails handling. #7276 has more in-depth desires which would be handy.

[rasos]

For the use case of deletion this is a duplicate of https://github.com/nextcloud/mail/issues/4286#issuecomment-754065575

[guettli]

I have the vague feeling, that nobody is using the mail feature of Nextcloud. A mail user agent which does not support these steps is unusable for me:

1. search
2. select all mails which where found by the search
3. Do a bulk action on the selected mails.

Step 1 and 3 are implemented.

But Step 2 is missing.

I could click on 100 mails ... yes I could do it .... but I don't want to.

Is there anything I can do to get this done (except coding)?

I am willing to pay money.

[mat-m]

For the use case of deletion this is a duplicate of #4286 (comment)

No, I don't agree on the duplicate status. In #4286, user wants a dedicated button only for Trash folder. Here I want a "Select all" (not a "delete") button on every mailbox, and be able to choose my action, whether it's move, delete, mark as spam, favorite, forward as attachment, ...

[turboyz]

Same here, I'd need this feature so badly. I need to manage professionally hundreds of emails.

In Gmail for example they implemented a selection mode similar to the file selection for folder.

CTRL+left_click for selecting the single email SHIFT+left_click for selecting all the emails between your first selection and your last selection.