Same here on Ubuntu 10.04 x64 all updated from repositories at 2011-02-16, kernel 2.6.32-28-generic, Boinc 6.10.17+dfsg-3ubuntu1 (boinc-client)
No matter if I type or move the mouse, with the setting "use only if inactive for x minutes" boinc process continues working.
Same here on Ubuntu 10.04 x64 all updated from repositories at 2011-02-16, kernel 2.6.32-28-generic, Boinc 6.10.17+ dfsg-3ubuntu1 (boinc-client)
No matter if I type or move the mouse, with the setting "use only if inactive for x minutes" boinc process continues working.