Appreciation of the mark-all-as-read button

I never appreciated it until I found that proton mail does not have one. My inbox there makes me cringe.

I'm in proton mail on FF I select all inbox in the select box upper right hand corner of the inbox ui.

all conversations on page selected - says You selected 50 conversations. next to it link text - Select all 2638 in inbox.

clicking select all 2638 in inbox selects all conversations.

next to checkbox where I selected conversations is a row of icons, first icon is an open mail that has the title "Mark all as read R"

When I use Mark all as read on selected conversations they become read, however they are still selected which is makes this stuff somewhat unclear.