Since upgrading to 3.0 and now 3.1, I've notice the Measure Tool (esri_mapping_measureDistanceTool) to be acting differently than before.
When measuring distances that had multiple verticies I am pretty sure I used to only see the end result which was great and this may have been a setting I did so that each individual verticies weren't measuring.
Now when I measure, I'm getting a constantly expanding tool with each added vertex I add, and this is annoying (I swear I had it so it didn't do this prior 3.0).

I noticed some changes in the tool as well, including the settings (cog wheel) no longer being shown and wonder if that's where the setting to prevent this was set?
Pre 3.0

Post 3.0

Am I imagining this, or was there a way to only show the end result measure and not all the verticies in between prior to 3.0?