allow multiple instances + adding new data source

hi,
there is a bug when adding new data sources while two instances of RDM are running.
tested with two instances of RDM:
add data source to instance no. 2 results in not saving the datasource
add data source to instance no. 1 results in showing nothing but white space where the sessions tree should appear and the version on the right bottom of RDM shows "1.0"

KR
plague