Symptoms

While using Multi-Select control where you have 2 boxes and can move items from the left box to the right selecting items you can use Text property as a Value and as a Display Name for the control. But if you would like to sort the control by another number property within source SmO and set up sorting inside 'Populate control with data' rule it is simply ignored. The items in the left box are sorted by the Display Name property irrespectively of sorting configured inside of 'Populate control with data' rule.
 

Diagnoses

This is known issue in K2 4.6.11 which has been resolved in 4.7 release (internal ID 555403):
K2 SmartForms MultiSelectControl - The control automatically sort the data by the Display name configured, even if no sorting was configured.

For 4.6.11 fix for this issue is included into CP 4611.16 rollup available upon request from K2 support.

 

Resolution

Consider upgrading to 4.7 or applying latest CP rollup for 4.6.11 (4611.16 or higher). 4.6.11 CP rollup is available upon request from K2 support.