Column order does not work as specified in xml for lookup component.

Support
#1
  1. Create a new project with only single entity e.g. Language with two attribute: code and name.
  2. Create standard screen: Browser.
  3. Change the column order in LAYOUT -> languageTable -> PROPERTIES(table) -> columns to change the name to 1st.

PROBLEM: when you open the Language window, the 1st column is still code instead of desired name.

#2

The order of columns is saved in user settings in the database when a user closes the screen. It may be the cause of your problem. Please take a look at this topic: UI components sometimes not updated - CUBA.Platform