Library, multiple windows, same process.
In Windows 7 Firefox 60.0.2 (32-bit) if I shift-clicked the "Library" tab in the WindowsTaskBar I would get a new instance of _"Library"_ which is TREMENDOUS for searching my [huge / years-cured] History when already searching something in it. In Win 8, Firefox 65 (64-bit), the action above generates a new browsing window. I would like to have the FIRST behavior.
ప్రత్యుత్తరాలన్నీ (1)
Sorry, but what exactly are you Shift+clicking? If I Shift+click the thumbnail image of the Library, Windows just focuses that window, nothing new opens.
If you want to open the Library in a regular tab, you can paste this address in the address bar and press Enter to load it. Or bookmark it and use that to launch a new window:
chrome://browser/content/places/places.xul