I have a number of "scratch" sessions that I use to tinker with more or less random projects, which can be big. I reuse those sessions because of their session-wide settings including which plugins are to be loaded (or not).

More often than not I am not certain that I'm done with a given project when I close the session. So next time around that I want to reuse the session I have to wait for all projects to be opened and documents to be restored, which costs time and other resources (see also D18551). This is esp. noticeable on Mac where I'm more likely to work with ObjC/++ files; parsing those causes significantly higher memory pressure which can be relieved only by restarting the session after closing the project containing those files (or at least the files in question but that's not the point here).

The session picker does show the list of projects a given session will open, and already gives the possibility to delete a session. It would be nice to add an additional button that triggers a simple interface that allows to (un)check projects from that session. How hard would that be?