Hi Rainer,How can i avoid that Main-Screen is closed(hidden) when Session locks ?
I really don't know, but that is the purpose of Session Lock feature, to lock out the application until a valid user gets access to it again.
Also would be interesting to know how do display Exit button (in Loggin Form) for Re-Login
For that you will have to create your own Login form, which is very easy to do (see documentation) and add that functionality. Keep in mind that Session Lock will leave forms in their current state (ex: unsaved data, etc.) so you may also check for those things before closing any open form. There has been a couple of discussion about this in the forum, so search for the "Session Lock".