~/.telescope/session was parsed in the main process before dropping in the sandbox: that's no good. This moves the initialization of the ui events later in ui_main_loop and makes so that the fs process, after entering the sandbox, parses and sends the content of the last session back to the main process; when it's done the ui gets loaded and telescope is back rocking. I'm plannig to re-use the struct session_tab during the save session operation soon.

When enabled with the -S (or --safe) flag, prevent telescope from writing files to the disk.

this helps to correctly manage the tab bar when tab-bar-show is 1.