[cybmole]

I think it is agreed that sigil 7.1 is slower to open than old versions.

I make it about 5 seconds on my fast-ish PC - for program only, no book file.

could we see an evolution to having each book in its own tab within sigil, & only one instance of sigil running - that way it could be "closed" to taskbar when not needed ( same as with calibre) but would actually be still memory resident.
selecting a an epub would just open a new tab in that same instance.

or are there fundamental reasons why this will not ever happen ?

alternatively, have a single instance only preference setting - right now if I open & minimise sigil & then open an epub, a new instance of sigil is launched so there are 2 running. In single instance mode the program would load the newly opened file after first prompting to save existing work, if applicable. VLC player for example works like this.