I just upgraded to build 5916 and noticed that whenever I launch the application, it loads the workspace and then seems to scan every project before displaying them in the left workspace tab. Previously (i suppose) this was cached and the application launched much quicker.

Same here with 5919. It takes ages to start up and shut down. I've got a workspace with 19 projects on a network share and it takes over a minute to start up. It's not ideal.

Nothing has changed in the IDE. Seems that at some point your network started working slower or you installed some software that monitors network data.