Palisade gap near cliff, cannot place corner post?

[Horatius]

Off-topic, how did he get his client to show the quality (I assume) in inventory?

Try using Ender's client or in case you already do, update it. There may be other clients with the same feature though.

[Datgum]

Okay, thanks for everyone's help. I kept playing around with the Shift method, and finally was able to place a sign that will block any intruders.

This next question is more anal retentive - I want to make sure my Gate setup looks right before I build yet another Initial Cornerpost. I placed two fire signs in between the first Post and where I am building the second one, and did not hold down shift for any of these placements. This looks correct, yeah?

[Girlinhat]

Gate needs 2 tiles between cornerposts to be constructed, assuming they're snapped to grid. You'll be able to have the option even if the space is occupied too, just won't have empty space to build it. That screenshot will work.