Hi,
You do not need an attachpoint to make a part clickable. In the image below I chose the fire handles (which do nothing in my VC) and added the Mouse Rectangle switch_landing_light:
View attachment 46173
When I load the VC into FSX, I can click on the fire handles and the landing lights turn on and off:
View attachment 46174
There is no attachpoint at the fire handles.
Note that if your code does not include a MouseRect section that part will not be clickable. Also, if you *only* have a MouseRect section I'm not sure that works? I've never tried it though.
Hope this helps,