Quite often I notice that Rhino 7 will produce some messy extension lines where they are not necessary. That usually happens after I change the position of the arrows from outside to inside. Usually there are two unnecessary extensions placed at either end, but in rare occasions only one end of the dimension has it while the opposite end is fine. Hopefully the dimensions could be made smarter in a future Rhino 7 update, so that they will never extend past the arrow’s tip. 
Since I use Rhino 7 I’m forced to additionally edit many of my drawings in a graphics program to manually erase those unnecessary extensions.
Note: The bug is not caused by the custom value in the text field. It happens on default (non-modified) dimensions all the time.
Messy dimension.3dm (67.1 KB)
