I just started experimenting with OpenLayers 4, and I have the following problem:
I have a map with a default raster(OSM), and on top of it a vector layer for drawing features, that covers only a small area. Now when I start drawing (e.g.) a polygon within this area(orange) I don't want the user be able to pull the blue form(form to be drawn) out of this while editing. Or just disable drawing geometry features on the raster layer.