To expand slightly:
When changing configuration from Flap 0 to Flap 1 the 100 knot switch is correct. ie Below 100 knots (on the ground selecting a take off flap setting you get both slats and flaps at setting 1), above 100 knots (ie decelerating and generally descending to wards landing you only get the slats)
When moving the lever from Flap 2 to Flap 1 a similar trigger occurs at a speed of 210knots IAS.
Above 210 knots you only get the slats, below this you get both.
If you actually accelerate through 210knots with both the flaps and slats extended in config 1 then the flaps will automatically retract.