The Picker of the ComboBox, has by default a maxHeight of 300 px. If the list of elements is bigger that 300 pixels, then a scrollbar will be added.
This behaviour was broken with ExtJS4, but now works correctly with ExtJS6.
This fixes the problem that this ComboGrid was displayed with an empty value
( similar the to the Keyboard Selection and Realm Selection in the login window)
An component id 'comment' is already defined for the column Comment of UserView.js causing here a conflict.
It seems ExtJS6 is more stringent about that than ExtJS4.