Dimensioning 3D solids in paper space question

[Anonymous]

Dear autocad community,

this is my first time asking for your help - unfortunately I couldnt find any solution by searching so far. 
When I try to dimension something just nothing happens after I set up the avaible options. 
I pick two points and set up the hight of the dimension line, after this a field pops up with the distance so I press enter to confirm the settings and everything just disappears.

This is in the layout section and I picked the distance between the two top edges. 
After I confirm the 45 with enter or "closing editior" it just disapears.

I am using AutoCAD Mechanical 2015 64bit 

edit: with the flatshot command I am able to dimension the new 2D modell, but with the 3D body its not working.

Thanks for your help

Robin