When the program is running standalone (no printer connected):
When you change the configuration settings of the printer setting of: Delta printer with cylindrical print shape: changing the diameter wil not update in the viewing window (the corresponding setting in repetier host in Windows is 'radius' )
Only when you switch the printer to another type and then back to Delta printer with... etc. will the new configuration be shown in the 3D window. In the Windows version of repetier host this is changed immediately.