Fixed code for positioning modal child window when parent is on screen whose coordinates are negative (wrt primary screen).
Fixed code for positioning modal child window when parent is on screen whose coordinates are negative (wrt primary screen).

sillsdev/libpalaso,gmartin7/libpalaso,gmartin7/libpalaso,gmartin7/libpalaso,gmartin7/libpalaso,sillsdev/libpalaso,sillsdev/libpalaso,sillsdev/libpalaso