It only took a decade and much of the EU is wondering where to find trained work force to onduct hundreds of thousands of jobs that remain vacant.

Germany, where this problem is the worst, has been recruiting work force from east European and Balkan countries for years. "Even the ad hoc opening of borders for refugees in 2015 fits in this framework."

It also wants to simplify the acceptance of workers from third countries, and has been advising potential labour force to take German language courses so that they already know the basics when they actually move to the country.

But recruitment of workers from abroad poses a problem for the countries of origin. "It often creates the same problem that the destination countries are trying to solve."

The positive effects of the single market for individuals can soon become a nightmare for their countries of origin - daily newspaper Delo says.