A (imho) popular usecase to open a new tab in Firefox on Linux is to have a URL selected in some window and paste it via middle click into the content area of the new tab. Since about:newtab is mainly occupied by links to popular sites it is currently needed to make sure to paste it in the free area around the screenshots/links. A middle mouse click on a screenshot opens the hovered site instead of pasting the URL to open the selection. I'd say it's more appropriate to open that only with left mouse click and keep pasting a selected URL with middle mouse click regardless of the mouse pointer position.
Mass-move to Firefox::New Tab Page. Filter on new-tab-page-component.
Component: Tabbed Browser → New Tab Page
You need to log in before you can comment on or make changes to this bug.