Dear Gianluca thank you so much, works indeed, yet I get a continuous flow of warnings upon moving the locator to the boundary:
LinearSolve::luc: Result for LinearSolve of badly conditioned matrix {{3.71649*10^13,3.71649*10^13},
{3.71649*10^13,3.71649*10^13}} may contain significant numerical errors. etc.
How could I overcome this?
Tx in advance,
best regards
Andras