Locus is restarted after longer phone call

[mambofive]

Probably not a Locus problem (that's why I post this here and not on getsatisfaction) - I think Android is responsible for this problem:

When I receive a phone call while navigation is active, Locus exits if the phone call takes longer (~10-15 mins). When the phone call ends, Locus is restarted, but the navigation track is gone. I have to stop somewhere and start a new navigation by choosing the destination again.

I know the Android task manager option to stop apps in background after some time if the display lock is active - but Locus for sure is not the list of apps to stop.

Does anybody know an Android setting which could be responsible for that? Android Version is 2.3.6.

 :idea: BTW, it would be more useful if Locus stayed in foreground while the phone call is active, so that I can still follow the navigation. On a previous phone running on Symbian, OviMaps stayed in foreground when a phone call was received. While the phone call was active, there was a green headset symbol in one corner of the map, but the map with the navigation was still in foreground.