Ah - I have the actual forum set to open when I switch to the tab - actually as I never switch off my PC but just set it on "Sleep",everything automatically opens as I left it. When I click on the forum I then click on "New Posts" to see if there is anything new. As I have four Windows open, each with a number of tabs, plus three "Edge" windows open, also with a number of tabs [do not ask] it means that when I wake my PC up everything is where I left it.
Luckily my PC, which was built for me, does what I want, as I am basically computer illiterate and totally self taught, and I have learned over time to set it how I want it. Not that I know what I am doing most of the time but it seems to work!
Regarding "all threads read" on this site- that shows up as "Mark Forums Read" on the line under "Home, Forums" etc immediately under "Home".
It has been a steep learning curve for me but mostly I get there. If not I know enough to close and restart my PC instead of panicking and calling my computer guru!
But I am still learning this site, just had to when changing from Windows XP Pro to Windows 7 Ultimate, and now to Windows 10. There are differences in all of them, just as there are differences in this site from others, especially since the change from vBulletin. And there is a difference from vBulletin to this new software. As I get used to it I like it more and more, but bugs do creep in as they do everywhere, which is why I am no doubt driving poor Admin round the bend!