Proposed feature:

1. Use the checkbox to select one or more email messages OR simply right-click on the desired email
2. Choose "Select all from sender" from the context menu
3. Proton selects ALL email from ALL the selected senders that are located in the current folder
4. User can then use the existing "Move" button to move them into a folder, "Delete" to delete them, "Label" to label them, etc.

That is it!

REASONING: This feature would be very powerful for users because it makes complicated, multi-step tasks MUCH faster, saving users time.

For example:

GOAL: Select multiple email from different senders and move them all into a single folder

EXISTING STEPS: (1) for the first sender, open the email, (2) click on the "From" field, (3) click on the copy button, (4) return to the previous folder, (5) click on the search bar, (6) type or copy/paste the email address into the sender box and confirm, (7) select all email, (8) move the email into the desired folder, (9) repeat steps 1-8 for EVERY SENDER whose email I wish to move into the desired folder. [TOTAL STEPS = 8 * number of senders]

PROPOSED STEPS: (1) check at least one email from each sender I wish to move, (2) right click and choose "Select all from sender", (3) click on the "Move" button, (4) select the desired folder. [TOTAL STEPS = 4]

Personally, the most common task I perform is moving email in order to maintain some sort of sanity for my inbox. Filters and labels are a huge help but it quickly gets out of hand (AND it's time consuming) to create filters for every sender. This feature would save me a bunch of time and close the gap between Proton Mail and more feature-filled email platforms like Outlook.