I’m trying to route a trace under the footprint of a module. (DIP in this case). I can draw the trace, but when I click to create a via to shift to a different layer, nothing happens. Are vias forbidden under footprints? Is there a workaround?
If you can place the via outside of the footprint as expected, I guess there might be a clearance issue. Check your via sizes etc. I assume you have layer visibility turned on for everything (right panel).
That has been my experience: When KiCAD refuses to place a via it’s either because it will pop through too close to a pad or trace; or because my default via size is larger than I intended it to be.
Dale
It must have been a clearance issue because now that I try it again on a clean layout I’m not having any problems. Unfortunately I’ve made too many changes to the design that was giving me problems to be able to be sure that was the issue, but it makes sense.
Thanks.
With:
PcbNEW -> View -> “Switch Canvas to openGL [F11]”
you can, well, switch the canvas to openGL 
This does however do much more then just use a different rendering engine.
One of the most convenient changes is that if you are placing or moving a trace or via, other traces/vias are shoved out of the way to create room for the new trace or via.
This is an extremely usefull feature, especially when routing (already densly populated areas) as it can shove multiple traces & vias to create room for the last few traces you want to add to your board. A real time saver.