Hi, i have find a bogu with the Dimension style.
https://smc2.box.com/s/yjhtci09vucjdhyw7qn3yx7249knfctv
on the link file Test Dim.3dm, if I open the file then it’s impossible to change the dimension style
but if I open a new rhino project and i import Test Dim.3dm then it’s possibl to change the dimension style!! 
Hello - so far this works here in 6.5. Just as a shot in the dark, can you please try closing and re-opening Rhino - does that behave any differently?
-Pascal
Hello, i have restart my computer and i have open the file Test Dim.3dm and the problem is still there.
I have creat a little video of my screen computer for explain the problème.
Please download the zip file and open with VLC (you do not have to decompress it)
and see the bog.
Best regards
@SMC2 The link doesn’t contain a zip file. It’s “test performance rhino6.3dm”. Did you link the wrong thing?
-David
Oups Sorry i have poste a wrong link
this is the good link 
https://smc2.box.com/s/yw2t0p07qj2k08cz5kxtc81vhc13yb9z
