That I would need most.

There should be setting in the main settings to prevent unlocking happening with keyboard open!

Maybe some daemon could be written to do this. If daemon notices a keyboard open event and the device was locked right before that, re-lock the device right away. Or not daemon, but a dbus-event script.

From system log when keyboard is opened during a non-secure lock:

Code:

Jan  9 19:12:48 Nokia-N900 ke_recv[1652]: prop_modified:1889: udi /org/freedesktop/Hal/devices/platform_slide modified button.state.value
Jan  9 19:12:48 Nokia-N900 kernel: [74061.655487] slide (GPIO 71) is now open
Jan  9 19:12:48 Nokia-N900 systemui-tklock[1257]: Method call received from: :1.1505, iface: com.nokia.system_ui.request, method: tklock_close
Jan  9 19:12:48 Nokia-N900 browser[1884]: GLIB CRITICAL ** hildon-1 - hildon_window_get_is_topmost: assertion `HILDON_IS_WINDOW (self)' failed

Looked for source code here http://mxr.maemo.org/fremantle/source/

Didn't find one for package osso-systemui-tklock (libsystemuiplugin_tklock.so). Is it closed source?