Preview on point (hover)

[grahamperrin]

From gomita/tabscope#65 (comment):

Mozilla bug 1385453 - Make it possible for async tab switcher to "warm up" tabs that are likely to be displayed soon - bugzilla.mozilla.org

• RESOLVED FIXED in Firefox 57
• referred from Photon Engineering Newsletter #15 | Dolske's blog - dolske.wordpress.com (2017-09-11).

Might 1385453 help to allow previewing of tabs that have not been clicked?

(Is the Firefox Quantum phrase 'discarded'? I lose track.)