Non-slavic countries who uses "Slavic colors" – USA, Britain, Australia, Anquilla, Bermuda, Burma, Cambodia, Chile, Congo, Cuba, Costa Rica, Dominican Republic, Faroe islands, France, Haiti, Iceland, North Korea, Laos, Malaysia, Netherlands, Thailand and alot more.

The Flag of Costa Rica, prior to 1848, had two blue stripes on top and bottom, and white in the center.  All Central American flags had this as memory of their short lived unification of the Federal Republic of 1821-41.  The Red was added to commemorate the French revolt of 1848 and creation of the Second Republic. 

Blue is for strength and perseverance and opportunity. 

White is for peace and wisdom

Red is for the blood of the people who died to save the nation from the invasion of William Walker and General Morazan. 

The Pan-Slavic flag was created in 1848 as well.  Sometimes things happen in two places at the same time.  The Pan Slavic flag was created a few months before Costa Rica's, but technically, there was no nation using the pan Slavic flag as a national flag at that time.  The Austrian Emperor accepted the tricolor as flags of Croatia and Slovenia, but does that count, being that they were not independent states?  The Costa Rican one was adopted in November of 1848.