The "previous output" text gets cut off in the command block GUI.
Ever since the "@s" selector was added to command block GUI's in 17w17b, it seems to push the "previous output" text downward, in back of the text box, as shown in the attached picture.
2017-04-29, 06:05 PM
2017-04-29, 06:37 PM
2017-04-29, 06:37 PM
0
0
-