Current situation:

It's not possible to place dripstone on certain blocks, which makes sense (chests, hopper, colweb).

But we are also not able to place it on leaves, dirt path and powder snow

while it is possible to place it on glass block, glowstone, fence, fence gates, ice, snow

Solution

it should not be possible to place dripstone on fences and gates

As for leaves, dirt path and powder snow, glass block, glowstone, ice, snow.. I think it's debatable if they should be able to place dripstone on them, just have to be consistent in the logic.