Cascading drop down menus in table row

Hi

I would really appreciate some help on the following issue:

A table is used for data display/user input. 4 columns are in it: Date, Continent, Country, City.

Only Date field is populated by backend service (Main_serv). Other fields are initially blank and are not populated by Main_serv.

The 3 columns are drop down menus: their entry lists are dynamically populated from backend.

Continent entry list is populated by a backend service (Cont_serv) which takes no input parameter.

Country entry list is populated by a backend service (Country_serv) which takes 1 input parameter: Continent

City entry list is populated by a backend service (City_serv) which takes 1 input parameter: Country.

For each table row, Users should select a Continent, then Country shold be dynamically populated, users should choose Country... and so on.

Table is editable, single selection. Date field is disabled to make it uneditable.

What happens is this:

Country and City in row X ignore what the users selects, unless row X is clicked and highlighted.

If a row where user has previously enter data is clicked or hovered, data randomly disappears and reappears from Country and City.

I believe dynamic entry lists are somehow refreshed upon row click as this problem affects only Country and City.

Continent does not depend on any parameter -> it works ok.

What I tried:

table uneditable: irresponsive

typical drop down box workaround (global entry list, hidden fields): no use

Help would be highly appreciated and rewarded.

Thanks in advance

Vincenzo