0.18.2 - Display update bugfix

Since nexxt got a lot leaner with when and what it should update visually in 0.18, there was the possibility there'd be one or two unnoticed "false positives". 
This turned out to be the case. 

Some visual updates - low-priority nametable & canvas tasks - were "forgotten about" in some cases they shouldn't. 
This has now been fixed.