Yes, I bet you have one :-) Just look here:
c:\users\<your-name>\AppData\Local\plastic4\guiclient.conf
Here's mine:
C:\Users\pablo\AppData\Local\plastic4>type guiclient.conf | grep Drive
<ShowMountPlasticDrive>true</ShowMountPlasticDrive>
The feature is pretty experimental yet, but should be fully usable. It is an improved "glassfs" which has been there for quite a long time, but with some tweaks to make it more usable.
It is very useful to take a look at the code using your Visual Studio without switching branches (although the first time you launch it it will be slow, since VS reads all the files in the solution, but then they're cached and next run will fly!).