Use menu context for screen and global search

issue3858
review5211002
Use the same read limit for children

review5121002
Explicitly set value of parent field

issue3819
review5061002
Fix update completion for empty reference

issue3890
review12271002
Use the right widget to get text in Char widget

issue3898
review9301002
Use Group.child_name instead of relation_field to skip on_change values

relation_field is not reliable see issue3899

issue3819
review9311002
Use a tuple model, dictionary for Reference field

issue3902
review9331002