I have one of these in green and another one in yellow, and have never managed to find out whodunnit. The shape has been done by many makers, notably in Sweden and in France, but copied in a lower (MUCH) lower quality by Ikea and others.
If you twist my arm I'd say, one of the many many Swedish makers. Flygsfors would have been signed and it has a white contour line, so they are out. Eda, Enneryd, Gullaskruf, Skruf, Kosta, Glimma - just go down the list and despair.