This should work, but I haven't tried it myself (because I only have 1 lamp per location). The manual says:
Pairing and connecting multiple lamps:
You can pair and connect a wireless controller with multiple lamps to operate multiple lamps simultaneously. If the distance between the controller and these lamps is within 1 metre, the lighting patterns of these lamps will change simultaneously.
Velcro or cable ties. It's a smooth surface, but without a mount etc. DIY is the order of the day. The angle may no longer fit or the position may be too high. Try it out - the light gain makes up for all the disadvantages.
Did you take out the batteries and disconnect the Screenbar from its power source in the first line? If yes, reconnecting the remote with the Screenbar might help.
https://www.youtube.com/watch?v=dn6DFRBxh3U
We work with daily prices, which can be influenced by various factors such as purchasing conditions, stock levels and supply and demand. These differ from our Swiss and international shop, so it is not so easy to make direct price comparisons.