It will indicate that a long click is being recorded. Instead, wait for the little tab animation to appear just above the cursor. Left-click the link but do not release the button. Install QuickTab and then navigate to a page with a link you’d like to open. It lets you open a link in a new background tab by clicking on it longer than you normally would if you wanted to open it in the current tab. If you’re a Firefox user though, QuickTab is an add-on that can help you. The mouse wheel is my preferred way of opening links in new, background tabs but when using the touchpad, the option just isn’t there.
To open a link in a new tab, we either right-click it and use the ‘Open link in new tab’ option from the context menu, or if we’re using a mouse instead of a touchpad, we use the mouse wheel and ‘middle click’ on the link.