Declarative landmark proximity filter eats memory

If the 'center' property of the LandmarkProximityFilter is bound to a coordinate (e.g. PositionInfosource),
every time the coordinate changes, LandmarkProximityFilter will internally bind for changes in lat/lon.

Since with PositionInfosource the actual coordinate object instance remains the same (won't be deleted in between), this means that the filter binds couple new connections on each update. Run the app for minute with one second update interval, and there are already 120 connections.