It seems that in FW 6.1.35R2 the channel input impedance setting softkey disappeared.
Also in the actual manual SDS1000X-ESDS1000X-U_UserManual_UM0101E-E05A.pdf the description is removed. No notice in release notes too!
I know that X-E has no 50

builtin, but if I used external Feedtrough then the information on the display will be usefull for documentation.