Looks like we cannot reproduce this. Please provide another test case to reproduce this issue.
Sencha Premium Member
Picker's displayField is not set correctly in generated code
1) Create an Ext.field.Select
2) Create model/store and properly associate the store with the picker
3) Set the 'displayField' value
4) Switch to Code view
5) Note that the displayField has been set WITHOUT single quotes around it, causing the code to fail at runtime
Attached image shows the effect of setting location as the displayField in my picker. Note that the code view has location without single quotes.
Thanks for reporting this, I'm opening a bug ticket to get it fixed.
In the meantime, try adding the quotes in the value manually.
Sencha Architect Development Team
Thanks for the bug report, this has been addressed.